WO2023107537A1

WO2023107537A1 - Antibody compositions and methods for utilizing with extracellular vesicles and microbes

Info

Publication number: WO2023107537A1
Application number: PCT/US2022/052093
Authority: WO
Inventors: Tanmoy GANGULY; Daniela Beccati; Divya Raghunathan; Aula ALAMI; Shannon ARGUETA
Original assignee: Evelo Biosciences, Inc.
Priority date: 2021-12-07
Filing date: 2022-12-07
Publication date: 2023-06-15

Abstract

Compositions and methods are provided for characterizing and purifying microbes and extracellular vesicles obtained therefrom.

Description

ANTIBODY COMPOSITIONS AND METHODS FOR UTILIZING WITH EXTRACELLULAR VESICLES AND MICROBES CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of the following U.S. Provisional Application Nos: 63/286,934, filed December 7, 2021, and 63/349,834, filed June 7, 2022, and the entire contents of each are incorporated herein by reference. BACKGROUND [0002] Microbial extracellular vesicles (mEVs), which can be used for a variety of purposes, including therapeutic applications, can be obtained and/or derived from different types of bacteria. Accordingly, there is a need in the art for methods and compositions for purifying mEVs and accurately identifying the source, as well as for identifying the presence and/or quantitating the amount of mEVs in a sample. SUMMARY [0003] In certain aspects, provided herein are methods and compositions useful in the purification or analysis of microbes (e.g., bacteria) and microbial extracellular vesicles (mEVs, such as secreted mEVs (smEVs) or processed mEVs (pmEVs), which can be obtained and/or derived from bacteria). In certain embodiments, provided herein are methods utilizing antibodies to purify a certain type of bacteria or mEVs (e.g., bacteria of a particular species or strain or mEVs thereof). Certain methods provided herein can be useful, e.g., in manufacturing and/or purifying bacteria or mEVs (e.g., in purifying bacteria or mEVs from a composition (such as a solution) comprising the bacteria of mEVs). In certain embodiments, provided herein are various methods (e.g., ELISA, surface plasmon resonance (SPR), Western blot, flow cytometry, microscopy, etc.) utilizing antibodies to detect and/or quantify a certain type of (e.g., target) bacteria or mEVs in a sample (e.g., bacteria of a particular species or strain or mEVs obtained and/or derived therefrom). In certain embodiments, a method of the present disclosure can include detecting and/or quantifying bacteria or mEVs in a sample, such as a sample that includes excipients, includes a drug substance (DS), and/or is in a sample dosage form (drug product (DP)), e.g., without interference from the excipients. In other embodiments provided herein, the various methods utilizing antibodies may be used to detect and/or quantify a certain type of bacteria or mEVs in a sample, such as a sample (e.g., blood sample) from a subject. In certain embodiments, provided herein are antibodies (and antigen binding fragments thereof) that can be used to detect and/or quantify certain types of bacteria and/or mEVs obtained and/or derived from certain types of bacteria. In certain embodiments, provided herein are affinity purification methods utilizing antibodies to isolate a certain type (e.g., species or strain) of bacteria or mEVs in a sample. For example, in some embodiments, the antibodies and antigen binding fragments thereof can be used to detect and/or quantify bacteria of the genus Prevotella and/or Fournierella and/or Veillonella, and/or mEVs obtained and/or derived from such bacteria. In some embodiments, the antibodies and antigen binding fragments thereof can be used to detect and/or quantify bacteria of the species Prevotella histicola and/or Fournierella massiliensis and/or Veillonella parvula, and/or mEVs obtained and/or derived from such bacteria. In some embodiments, the antibodies and antigen binding fragments thereof can be used to detect and/or quantify bacteria of the strain Prevotella Strain B 50329 (NRRL accession number B 50329) and/or Fournierella massiliensis Strain A (ATCC Deposit Number PTA-126696) and/or Veillonella parvula Strain A (ATCC Accession Number PTA-125691), and/or mEVs obtained and/or derived from such bacteria. [0004] In certain aspects, provided herein are antibodies and antigen binding fragments thereof. In some embodiments, the antibody or antigen binding fragment thereof comprises one or more (e.g., 1, 2, 3, 4, 5, or 6) heavy or light chain CDR (e.g., CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and/or CDRL3) sequences set forth in Table 1. In certain embodiments, the antibody or antigen binding fragment thereof comprises a heavy chain variable region sequence set forth in Table 1. In certain embodiments, the antibody or antigen binding fragment thereof comprises a light chain variable region sequence set forth in Table 1. In some embodiments, the antibody comprises a heavy chain sequence set forth in Table 1. In some embodiments, the antibody comprises a light chain sequence set forth in Table 1. In certain embodiments, the antibody or antigen binding fragment thereof comprises a heavy chain variable region and a light chain variable region sequence set forth in Table 1. In some embodiments, the antibody comprises a heavy chain sequence and a light chain sequence set forth in Table 1. In certain embodiments, the antibody or antigen binding fragment thereof comprises a heavy chain variable region and a light chain variable region sequence from 02F09-02B04 mAb. In some embodiments, the antibody comprises a heavy chain sequence and a light chain sequence from 17B01-02G10 mAb. [0005] Table 1: Representative Antibody Sequences

[0006] In some embodiments, the antibody comprises a heavy chain CDR3 of SEQ ID NO: 5. In certain embodiments, the antibody further comprises a heavy chain CDR1 of SEQ ID NO: 3 and a heavy chain CDR2 of SEQ ID NO: 4. In some embodiments, the antibody comprises a heavy chain variable region having a sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to SEQ ID NO: 2. In some embodiments, the antibody comprises a heavy chain variable region of SEQ ID NO: 2. In some embodiments, the antibody comprises a heavy chain having a sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to SEQ ID NO: 1. In some embodiments, the antibody comprises a heavy chain of SEQ ID NO: 1. In some embodiments, the antibody comprises a light chain CDR3 of SEQ ID NO: 10. In certain embodiments, the antibody comprises a light chain CDR1 of SEQ ID NO: 8 and a light chain CDR2 of SEQ ID NO: 9. In some embodiments, the antibody comprises a light chain variable region having a sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to SEQ ID NO: 7. In some embodiments, the antibody comprises a light chain variable region of SEQ ID NO: 7. In some embodiments, the antibody comprises a light chain having a sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to SEQ ID NO: 6. In certain embodiments, the antibody comprises a light chain of SEQ ID NO: 6. [0007] In some embodiments, the antibody comprises a heavy chain CDR3 of SEQ ID NO: 15. In certain embodiments, the antibody further comprises a heavy chain CDR1 of SEQ ID NO: 13 and a heavy chain CDR2 of SEQ ID NO: 14. In some embodiments, the antibody comprises a heavy chain variable region having a sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to SEQ ID NO: 12. In some embodiments, the antibody comprises a heavy chain variable region of SEQ ID NO: 12. In some embodiments, the antibody comprises a heavy chain having a sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to SEQ ID NO: 11. In some embodiments, the antibody comprises a heavy chain of SEQ ID NO: 11. In some embodiments, the antibody comprises a light chain CDR3 of SEQ ID NO: 20. In certain embodiments, the antibody comprises a light chain CDR1 of SEQ ID NO: 18 and a light chain CDR2 of SEQ ID NO: 19. In some embodiments, the antibody comprises a light chain variable region having a sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to SEQ ID NO: 17. In some embodiments, the antibody comprises a light chain variable region of SEQ ID NO: 17. In some embodiments, the antibody comprises a light chain having a sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to SEQ ID NO: 16. In certain embodiments, the antibody comprises a light chain of SEQ ID NO: 16. [0008] In certain embodiments, the antibody or antigen binding fragment thereof provided herein binds to mEVs obtained and/or derived from bacteria of the genus Prevotella (e.g., bacteria of the species Prevotella histicola, such as bacteria of the strain Prevotella Strain B 50329). In some embodiments, the antibody or antigen binding fragment thereof provided herein binds to bacteria of the genus Prevotella (e.g., bacteria of the species Prevotella histicola, such as bacteria of the strain Prevotella Strain B 50329). In some embodiments, the antibody provided herein competes for antigen binding with an antibody having a having a heavy chain sequence of SEQ ID NO: 1 and a light chain sequence of SEQ ID NO: 6. In some embodiments, the antibody provided herein competes for antigen binding with an antibody having a having a heavy chain sequence of SEQ ID NO: 11 and a light chain sequence of SEQ ID NO: 16. [0009] In some embodiments provided herein, the antibody or antigen binding fragment thereof binds to mEVs obtained and/or derived from bacteria of the genus Fournierella (e.g., bacteria of the species Fournierella massiliensis, such as bacteria of the strain Fournierella massiliensis Strain A (ATCC Deposit Number PTA-126696)). In some embodiments provided herein, the antibody or antigen binding fragment thereof binds to bacteria of the genus Fournierella (e.g., bacteria of the species Fournierella massiliensis, such as bacteria of the strain Fournierella massiliensis Strain A (ATCC Deposit Number PTA-126696)). [0010] In some embodiments provided herein, the antibody or antigen binding fragment thereof binds to mEVs obtained and/or derived from bacteria of the genus Veillonella (e.g., bacteria of the species Veillonella parvula, such as bacteria of the strain Veillonella parvula Strain A (ATCC Accession Number PTA-125691)). In some embodiments provided herein, the antibody or antigen binding fragment thereof binds to bacteria of the genus Veillonella (e.g., bacteria of the species Veillonella parvula, such as bacteria of the strain Veillonella parvula Strain A (ATCC Accession Number PTA- 125691)). [0011] In certain aspects, provided herein is a nucleic acid molecule comprising a sequence encoding a heavy chain variable region and/or a light chain variable region of an antibody provided herein or antigen binding fragment thereof. In certain aspects, provided herein is a vector comprising such a nucleic acid. In some embodiments, provided herein is a host cell comprising a nucleic acid and/or vector provided herein. [0012] In certain aspects, provided herein is a nucleic acid molecule comprising a sequence encoding a heavy chain and/or a light chain of an antibody provided herein or antigen binding fragment thereof. In certain aspects, provided herein is a vector comprising such a nucleic acid. In some embodiments, provided herein is a host cell comprising a nucleic acid and/or vector provided herein. [0013] In certain aspects, provided herein is method of detecting (e.g., identifying) the genus, species and/or strain of bacteria from which mEVs in a sample are obtained and/or derived (bacterial mEVs). In some embodiments, the method comprises: (a) contacting the sample comprising the mEVs with an antibody or antigen binding fragment thereof that specifically binds to an antigen on the mEVs; and (b) detecting the binding of the antibody or antigen binding fragment thereof to the mEVs, thereby detecting (e.g., identifying)and/or quantifying the genus, species and/or strain of bacteria from which the mEVs are obtained and/or derived (e.g., using ELISA, flow cytometry, SPR, Western blot or microscopy). [0014] In certain embodiments, the antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof that specifically binds to an antigen on a certain type of bacterial mEVs. In certain embodiments, the antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof provided herein. In some embodiments, the antibody or antigen binding fragment thereof specifically binds to an antigen on mEVs obtained and/or derived from bacteria of the genus Prevotella (e.g., bacteria of the species Prevotella histicola, such as bacteria of the strain Prevotella Strain B 50329). In some embodiments provided herein, the antibody or antigen binding fragment thereof specifically binds to an antigen on mEVs obtained and/or derived from bacteria of the genus Fournierella (e.g., bacteria of the species Fournierella massiliensis, such as bacteria of the strain Fournierella massiliensis Strain A (ATCC Deposit Number PTA- 126696)). In some embodiments provided herein, the antibody or antigen binding fragment thereof binds to mEVs obtained and/or derived from bacteria of the genus Veillonella (e.g., bacteria of the species Veillonella parvula, such as bacteria of the strain Veillonella parvula Strain A (ATCC Accession Number PTA-125691)). [0015] In certain embodiments of the compositions and methods provided herein, the antibody or antigen binding fragment thereof is detectably labeled. [0016] In some embodiments, the antibody or antigen binding fragment thereof is immobilized on a solid support. In some embodiments, the solid support may be any one of, but are not limited to, the following: biochips, microwells, beads, columns, flow cells, and membranes. In some embodiments, the solid support is a bead. In some embodiments, the bead is a latex bead. In some embodiments, the bead is a magnetic bead. In some embodiments, the bead is an agarose bead. In some embodiments, the solid support is a column. In some embodiments, the column is any one of, but are not limited to, the following: protein A, protein G column, streptavidin column, spin-column, and resin columns. [0017] In certain embodiments of the composition and methods provided herein, the mEVs are immobilized on a solid support. In some embodiments, the solid support is a bead. In some embodiments, the mEVs are conjugated to a latex bead. In some embodiments, the latex bead is a super active latex bead. In some embodiments, the super active latex bead is an aldehyde/sulfate bead. [0018] In certain aspects, provided herein is method of quantifying the genus, species and/or strain of bacteria from which mEVs in a sample are obtained and/or derived (bacterial mEVs). In some embodiments, the method comprises: (a) contacting the sample comprising the mEVs with an antibody or antigen binding fragment thereof that specifically binds to an antigen on the mEVs; (b) detecting the binding of the antibody or antigen binding fragment thereof to the mEVs; and quantifying the binding detected, thereby quantifying the genus, species, and/or strain of bacteria from which the mEVs are obtained and/or derived (e.g., using ELISA, flow cytometry, SPR, Western blot, or microscopy). In certain embodiments, the antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof that specifically binds to an antigen on a certain type of bacterial mEVs. In certain embodiments, the antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof provided herein. In some embodiments, the antibody or antigen binding fragment thereof specifically binds to an antigen on mEVs obtained and/or derived from bacteria of the genus Prevotella (e.g., bacteria of the species Prevotella histicola, such as bacteria of the strain Prevotella Strain B 50329). In some embodiments provided herein, the antibody or antigen binding fragment thereof specifically binds to an antigen on mEVs obtained and/or derived from bacteria of the genus Fournierella (e.g., bacteria of the species Fournierella massiliensis, such as bacteria of the strain Fournierella massiliensis Strain A (ATCC Deposit Number PTA-126696)). In some embodiments provided herein, the antibody or antigen binding fragment thereof specifically binds to an antigen on mEVs from bacteria of the genus Veillonella (e.g., bacteria of the species Veillonella parvula, such as bacteria of the strain Veillonella parvula Strain A (ATCC Accession Number PTA-125691)). [0019] In certain embodiments of the compositions and methods provided herein, the antibody or antigen binding fragment thereof is detectably labeled. [0020] In some embodiments, the antibody or antigen binding fragment thereof is immobilized on a solid support. In some embodiments, the solid support may be any one of, but are not limited to, the following: biochips, microwells, beads, columns, flow cells, and membranes. In some embodiments, the solid support is a bead. In some embodiments, the bead is a latex bead. In some embodiments, the bead is a magnetic bead. In some embodiments, the bead is an agarose bead. In some embodiments, the solid support is a column. In some embodiments, the column is any one of, but are not limited to, the following: protein A, protein G column, streptavidin column, spin-column, and resin columns. [0021] In certain embodiments of the composition and methods provided herein, the mEVs are immobilized on a solid support. In some embodiments, the solid support is a bead. In some embodiments, the mEVs are conjugated to a latex bead. In some embodiments, the latex bead is a super active latex bead. In some embodiments, the super active latex bead is an aldehyde/sulfate bead. [0022] In certain aspects, provided herein is method of detecting (e.g., identifying)the genus, species and/or strain of bacteria in a sample. In some embodiments, the method comprises: (a) contacting the sample comprising the bacteria with an antibody that specifically binds to an antigen on the bacteria; and (b) detecting the binding of the antibody to the bacteria, thereby detecting (e.g., identifying) the genus, species and/or strain of bacteria; and/or (c) quantifying the genus, species and/or strain of bacteria (e.g., using ELISA, flow cytometry, SPR, Western blot or microscopy). In certain embodiments, the antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof that specifically binds to an antigen on a certain type of bacteria. In certain embodiments, the antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof provided herein. In some embodiments, the antibody or antigen binding fragment thereof specifically binds to an antigen on bacteria of the genus Prevotella (e.g., bacteria of the species Prevotella histicola, such as bacteria of the strain Prevotella Strain B 50329). In some embodiments provided herein, the antibody or antigen binding fragment thereof specifically binds to an antigen on bacteria of the genus Fournierella (e.g., bacteria of the species Fournierella massiliensis, such as bacteria of the strain Fournierella massiliensis Strain A (ATCC Deposit Number PTA-126696)). In some embodiments provided herein, the antibody or antigen binding fragment thereof specifically binds to an antigen on bacteria of the genus Veillonella (e.g., bacteria of the species Veillonella parvula, such as bacteria of the strain Veillonella parvula Strain A (ATCC Accession Number PTA-125691)). [0023] In certain embodiments of the compositions and methods provided herein, the antibody or antigen binding fragment thereof is detectably labeled. In some embodiments, the antibody or antigen binding fragment thereof is immobilized on a solid support. In some embodiments, the solid support may be any one of, but isnot limited to, the following: biochips, microwells, beads, columns, flow cells, and membranes. In some embodiments, the solid support is a bead. In some embodiments, the bead is a latex bead. In some embodiments, the bead is a magnetic bead. In some embodiments, the bead is an agarose bead. In some embodiments, the solid support is a column. In some embodiments, the column is any one of, but isnot limited to, the following: a protein A column, protein G column, streptavidin column, spin-column, and resin column. [0024] In certain embodiments of the composition and methods provided herein, the bacteria are immobilized on a solid support. In some embodiments, the solid support is a bead. In some embodiments, the bacteria are conjugated to a latex bead. In some embodiments, the latex bead is a super active latex bead. In some embodiments, the super active latex bead is an aldehyde/sulfate bead. [0025] In certain aspects, provided herein is method of quantifying the genus, species and/or strain of bacteria in a sample. In some embodiments, the method comprises: (a) contacting the sample comprising the bacteria with an antibody that specifically binds to an antigen on the bacteria; (b) detecting the binding of the antibody to the bacteria; and (c) quantifying the detected binding, thereby quantifying amount of the genus, species and/or strain of bacteria in the sample (e.g., using ELISA, flow cytometry, SPR, Western blot or microscopy). In certain embodiments, the antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof that specifically binds to an antigen on a certain type of bacteria. In certain embodiments, the antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof provided herein. In some embodiments, the antibody or antigen binding fragment thereof specifically binds to an antigen on bacteria of the genus Prevotella (e.g., bacteria of the species Prevotella histicola, such as bacteria of the strain Prevotella Strain B 50329). In some embodiments provided herein, the antibody or antigen binding fragment thereof specifically binds to an antigen on bacteria of the genus Fournierella (e.g., bacteria of the species Fournierella massiliensis, such as bacteria of the strain Fournierella massiliensis Strain A (ATCC Deposit Number PTA-126696)). In some embodiments provided herein, the antibody or antigen binding fragment thereof specifically binds to an antigen on bacteria of the genus Veillonella (e.g., bacteria of the species Veillonella parvula, such as bacteria of the strain Veillonella parvula Strain A (ATCC Accession Number PTA-125691)). [0026] In certain embodiments of the compositions and methods provided herein, the antibody or antigen binding fragment thereof is detectably labeled. In some embodiments, the antibody or antigen binding fragment thereof is immobilized on a solid support. In some embodiments, the solid support may be any one of, but is not limited to, the following: biochips, microwells, beads, columns, flow cells, and membranes. In some embodiments, the solid support is a bead. In some embodiments, the bead is a latex bead. In some embodiments, the bead is a magnetic bead. In some embodiments, the bead is an agarose bead. In some embodiments, the solid support is a column. In some embodiments, the column is any one of, but is not limited to, the following: a protein A column, protein G column, streptavidin column, spin-column, and resin column. [0027] In certain embodiments of the composition and methods provided herein, the bacteria are immobilized on a solid support. In some embodiments, the solid support is a bead. In some embodiments, the bacteria are conjugated to a latex bead. In some embodiments, the latex bead is a super active latex bead. In some embodiments, the super active latex bead is an aldehyde/sulfate bead. [0028] In certain aspects, provided herein is a method of detecting (e.g., identifying) and/or quantifying the genus, species and/or strain of bacteria from which microbial extracellular vesicle (mEVs) in a sample are obtained and/or derived, the method comprising: (a) contacting the sample comprising the mEVs with a first antibody or antigen binding fragment thereof that specifically binds to an antigen on the mEVs; (b) contacting the sample comprising the mEVs with a second antibody or antigen binding fragment thereof that specifically binds to an antigen on the mEVs; and (c) detecting the binding of the first and/or the second antibody first and/or the second antibody or antigen binding fragments thereof to the mEVs (e.g., using ELISA, flow cytometry, Western blot or microscopy), thereby detecting (e.g., identifying) and/or quantifying the genus, species and/or strain of bacteria from which the mEVs are obtained and/or derived. In certain embodiments, the first and/or second antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof that binds to a certain type of bacterial mEVs. In certain embodiments, the first and/or second antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof provided herein. In some embodiments, the first and/or second antibody or antigen binding fragment thereof binds mEVs obtained and/or derived from bacteria of the genus Prevotella (e.g., bacteria of the species Prevotella histicola, such as bacteria of the strain Prevotella Strain B 50329). In some embodiments provided herein, the first and/or second antibody or antigen binding fragment thereof binds mEVs obtained and/or derived from bacteria of the genus Fournierella (e.g., bacteria of the species Fournierella massiliensis, such as bacteria of the strain Fournierella massiliensis Strain A (ATCC Deposit Number PTA-126696)). In some embodiments provided herein, the antibody or antigen binding fragment thereof specifically binds to an antigen on mEVs from bacteria of the genus Veillonella (e.g., bacteria of the species Veillonella parvula, such as bacteria of the strain Veillonella parvula Strain A (ATCC Accession Number PTA-125691)). [0029] In certain embodiments, the first antibody and/or the second antibody is detectably labeled. [0030] In certain aspects, provided herein is a method of detecting (e.g., identifying) and/or quantifying the genus, species and/or strain of bacteria in a sample, the method comprising: (a) contacting the sample comprising the bacteria with a first antibody or antigen binding fragment thereof that specifically binds to an antigen on the bacteria; (b) contacting the sample comprising the bacteria with a second antibody or antigen binding fragment thereof that specifically binds to an antigen on the bacteria; and (c) detecting the binding of the first and/or the second antibody or antigen binding fragments thereof to the bacteria (e.g., using ELISA, flow cytometry, SPR, Western blot or microscopy), thereby detecting (e.g., identifying) and/or quantifying the genus, species and/or strain of bacteria. In certain embodiments, the first and/or second antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof that binds to a certain type of bacteria. In certain embodiments, the first and/or second antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof provided herein. In some embodiments, the first and/or second antibody or antigen binding fragment thereof binds bacteria of the genus Prevotella (e.g., bacteria of the species Prevotella histicola, such as bacteria of the strain Prevotella Strain B 50329). In some embodiments provided herein, the first and/or second antibody or antigen binding fragment thereof binds bacteria of the genus Fournierella (e.g., bacteria of the species Fournierella massiliensis, such as bacteria of the strain Fournierella massiliensis Strain A (ATCC Deposit Number PTA- 126696)). In some embodiments provided herein, the antibody or antigen binding fragment thereof specifically binds to an antigen on bacteria of the genus Veillonella (e.g., bacteria of the species Veillonella parvula, such as bacteria of the strain Veillonella parvula Strain A (ATCC Accession Number PTA-125691)). [0031] In certain embodiments, the first antibody and/or the second antibody is detectably labeled. [0032] In certain embodiments, the first antibody or antigen binding fragment thereof is immobilized on (e.g., tethered to) a surface (e.g., a biochip, microwell, bead, column, or a membrane). In some embodiments, the mEVs or bacteria are captured on the surface by the first antibody or antigen binding fragment thereof, forming captured mEVs or captured bacteria. In some embodiments, the second antibody or antigen binding fragment thereof binds to the captured mEVs or captured bacteria. In certain embodiments, the second antibody is detectably labeled and step (c) comprises detecting the detectable label. In some embodiments, step (c) further comprises contacting the second antibody with a detectably labeled third antibody specific for the second antibody and further comprises detecting the detectable label. In certain embodiments, the second antibody is biotin labeled and step (c) further comprises contacting the second antibody with a streptavidin-labeled detectable label and further comprises detecting the detectable label. [0033] In some embodiments, the first antibody is contacted to the sample before the second antibody. In certain embodiments, the second antibody is contacted to the sample before the first antibody. In some embodiments, the first and second antibody are contacted to the sample simultaneously. [0034] In some embodiments, the first antibody or antigen binding fragment thereof competes for antigen binding with an antibody having a heavy chain sequence of SEQ ID NO: 1 and a light chain sequence of SEQ ID NO: 6 and the second antibody or antigen binding fragment thereof competes for antigen binding with an antibody having a having a heavy chain sequence of SEQ ID NO: 11 and a light chain sequence of SEQ ID NO: 16. In some embodiments, the first antibody or antigen binding fragment thereof competes for antigen binding with an antibody having a having a heavy chain sequence of SEQ ID NO: 11 and a light chain sequence of SEQ ID NO: 16 and the second antibody or antigen binding fragment thereof competes for antigen binding with an antibody having a having a heavy chain sequence of SEQ ID NO: 1 and a light chain sequence of SEQ ID NO: 6. [0035] In certain aspects, provided herein is a method of purifiying bacteria or mEVs (e.g., a type of bacteria or mEVs) from a solution (e.g., a fermentation solution). The method comprises: (a) contacting the solution comprising the bacteria or mEVs with an antibody or antigen binding fragment thereof that specifically binds to an antigen on the bacteria or mEVs; and (b) eluting the bacteria or mEVs from the antibody or antigen binding fragment thereof, thereby purifying the bacteria or mEVs from the solution. [0036] In certain embodiments, the antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof that specifically binds to an antigen on a certain type of bacteria or mEVs. In certain embodiments, the antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof provided herein. In some embodiments, the antibody or antigen binding fragment thereof specifically binds to an antigen on bacteria or mEVs obtained and/or derived from bacteria of the genus Prevotella (e.g., bacteria of the species Prevotella histicola, such as bacteria of the strain Prevotella Strain B 50329). In some embodiments provided herein, the antibody or antigen binding fragment thereof specifically binds to an antigen on bacteria or mEVs obtained and/or derived from bacteria of the genus Fournierella (e.g., bacteria of the species Fournierella massiliensis, such as bacteria of the strain Fournierella massiliensis Strain A (ATCC Deposit Number PTA-126696)). In some embodiments provided herein, the antibody or antigen binding fragment thereof binds to mEVs obtained and/or derived from bacteria of the genus Veillonella (e.g., bacteria of the species Veillonella parvula, such as bacteria of the strain Veillonella parvula Strain A (ATCC Accession Number PTA- 125691)). [0037] In certain embodiments of the compositions and methods provided herein, the antibody or antigen binding fragment thereof is detectably labeled. In some embodiments, the antibody or antigen binding fragment thereof is immobilized on a solid support. In some embodiments, the solid support may be any one of, but is not limited to, the following: biochips, microwells, beads, columns, flow cells, and membranes. In some embodiments, the solid support is a bead. In some embodiments, the bead is a latex bead. In some embodiments, the bead is a magnetic bead. In some embodiments, the bead is an agarose bead. In some embodiments, the solid support is a column. In some embodiments, the column is any one of, but is not limited to, the following: a protein A column, protein G column, streptavidin column, spin-column, and resin column. [0038] In some embodiments of the methods provided herein, the sample is from a drug substance, a drug product, a microbial (e.g., bacterial) culture, or an in-process sample from a step of a manufacturing or purification process. In some embodiments of the methods provided herein, the sample is from a subject (e.g., human) such as a subject to whom a composition has been administered. For example, the sample can be from blood, serum, saliva, urine, feces, bile, cerebral spinal fluid, semen, or vaginal fluid, from the subject. In some embodiments of the methods provided herein, the sample is from a subject’s blood. BRIEF DESCRIPTION OF THE DRAWINGS [0039] Figure 1 shows IgG levels detected in dilutions of serum collected on Day 0, Day 35 and Day 56/58. [0040] Figure 2 shows the cross-reactivity of P. histicola 1 polyclonal sera to mEVs from other bacteria. [0041] Figure 3 shows that hybridomas exhibit varied reactivity to different Prevotella bacteria. The reactivity to different Prevotellas is generally as follows P. histicola 1 = P. histicola 2 >> P. melanogenica. [0042] Figure 4 shows the relative signal detected when the 02F09 clone and 17B01 clone antibodies are used alternatively as coating and detection antibodies. [0043] Figure 5 shows negligible interactions between mEVs from P. histicola 1 injected at a concentration of 1, 2, 4, 8, 16, or 32 µg protein/mL and the isotype control antibody immobilized on Fc1. [0044] Figure 6 shows binding of mEVs from P. histicola 1 injected at a concentration of 1, 2, 4, 8, 16, or 32 µg protein/mL to the monoclonal antibody 17B01- 02G10 immobilized on Fc2. Sensorgrams were obtained after blank and isotype control subtraction. [0045] Figure 7 shows interactions between mEVs from P. histicola 1 drug substance (DS) injected at a concentration of 1, 2, 4, 8, 16, or 32 µg protein/mL and the isotype control antibody immobilized on Fc1. The higher the analyte concentration, the higher the resulting signal. [0046] Figure 8 shows binding of mEVs from P. histicola 1 drug substance injected at a concentration of 1, 2, 4, 8, 16, or 32 µg protein/mL and the monoclonal antibody 17B01-02G10 immobilized on Fc2. Sensorgrams were obtained after blank and isotype control subtraction. [0047] Figure 9 shows a negative control: Interaction of mEVs from Harryflintia acetispora injected at the concentration of 1, 2, 4, 8, 16, or 32 µg protein/mL and the monoclonal antibody specific for P. histicola 1 (17B01-02G10). Sensorgrams were obtained after blank and isotype control subtraction. [0048] Figure 10 shows that a sandwich ELISA with two monoclonal antibodies (17B01-02G10: capture antibody; 02F09-02B04: detection antibody) based on particle count distinguishes between mEVs from different strains of P. histicola: P. histicola 1 and P. histicola 2, and from another species of the same genus: P. melanogenica. [0049] Figure 11 shows the IgG titers of serum collected on different days (Day 0, Day 35 and Day 56/58). [0050] Figure 12 shows cross-reactivity of a F. massiliensis 1 polyclonal antibody to mEVs from other bacteria. [0051] Figure 13 shows that hybridomas exhibited varied reactivity to different Fournierella bacteria mEVs and little to no reactivity to H. acetispora and Megasphaera sp. mEVs. [0052] Figures 14A and 14B show the specificities of certain capture and detection antibodies. Figure 14A shows the specificity of clone 14C10-01C09 used as a capture antibody and other subclones as detection antibodies to F. massiliensis 1 and Megasphera sp. mEVs. Subclones listed in legend from top to bottom are shown in order in the graph from left to right. For example, the two boxed data sets refer to 17E01-02B12 and 17E01- 02G12. Figure 14B shows the specificity of clone 14C10-02C06 used as a capture antibody and other subclones as detection antibodies to F. massiliensis 1 and Megasphera sp. mEVs. Subclones listed in legend from top to bottom are shown in order in the graph from left to right. For example, the two boxed data sets refer to 17E01-02B12 and 17E01-02G12. [0053] Figures 15A-15D show that certain capture antibody/detection antibody combinations can distinguish the mEVs of two F. massiliensis strains from Megasphera sp. mEVs. Figure 15A shows that the monoclonal antibody can distinguish the mEVs of two F. massiliensis strains from Megasphera sp. EVs, in a particle-based sandwich ELISA when clone 14C10-01C09 is used as the capture antibody and clone 17E01-02B12 is used as the detection antibody. Figure 15B shows that the monoclonal antibody can distinguish the mEVs of two different F. massiliensis strains from Megasphera sp. EVs, in a particle- based sandwich ELISA when clone 14C10-01C09 is used as the capture antibody and clone 17E01-02G12 is used as the detection antibody. Figure 15C shows that the monoclonal antibody can distinguish mEVs of two F. massiliensis strains from Megasphera sp. EVs, in a particle-based sandwich ELISA when clone 14C10-02C06 is used as the capture antibody and clone 17E01-02B12 is used as the detection antibody. Figure 15D shows that the monoclonal antibody can distinguish mEVs of two different F. massiliensis strains from other Megasphera sp. EVs, in a particle-based sandwich ELISA when clone 14C10-02C06 is used as the capture antibody and clone 17E01-02G12 is used as the detection antibody. [0054] Figure 16 shows a standard curve generated with P. histicola 1 mEVs samples from different batches run in triplicate using the sandwich ELISA method described herein and the interpolated concentration (3.95 x 10¹¹ p/ml) of an unknown sample. The measured concentration of the unknown sample using NTA is 4.2 x 10¹¹ particles (p)/ml. [0055] Figure 17 shows the flow cytometry result for P. histicola 1 mEVs from a solution comprising the P. histicola 1 mEVs. DETAILED DESCRIPTION General [0056] Microbial extracellular vesicles (mEVs) having therapeutic uses can be obtained and/or derived from various types of bacteria. Accordingly, it is important to be able to accurately identify the source and quantitate the amount of mEVs in a sample. However, standard methods used to determine the identity of whole bacteria are nucleic acid based, and therefore may not be useful in assessing the identity of mEVs. In certain aspects, provided herein are methods and compositions in which antibodies are used to identify and/or quantify mEVs in a sample such as a solution and/or to accurately detect and/or quantify mEVs from a particular bacterial genus, species, or strain. In other aspects, the methods and compositions provided herein may also be used to detect the presence or absence of and/or quantify mEVs in a sample from a subject, for example, blood from a subject, such as after administration (e.g., oral, rectal, mucosal administration or by inhalation) of a composition comprising the mEVs to the subject. The methods and compositions may also be used to identify and/or quantify bacteria of a particular bacterial genus, species, or strain. [0057] As disclosed herein, in certain aspects, pairs of monoclonal antibodies can surprisingly be used to detect, quantify, identify, isolate, and otherwise characterize particular strains of bacterial mEVs. For example, monoclonal antibodies were developed that specifically recognized antigens present on mEVs of Prevotella histicola, Fournierella massiliensis and Veillonella parvula strains. By using particular antibodies as capture antibodies and different monoclonal antibodies as detection antibodies, P. histicola strain B 50329 mEVs could be distinguished from other mEVs of other bacteria, including other Prevotella species and strains. Additionally, one combination of antibodies used in a sandwich assay could distinguish mEVs of P. histicola strain B 50329 (also referred to herein as “P. histicola 1” or simply “P. histicola”) and mEVs of P. histicola ATCC designation number PTA-126140 (also referred to herein as “P. histicola 2”) based on particle count, and not generate any signal for mEVs obtained and/or derived from other, including closely related, bacteria (e.g., species of the same genus, e.g.. Prevotella melanogenica). [0058] In another example, by using particular antibodies as capture antibodies and different monoclonal antibodies as detection antibodies, mEVs of Fournierella massiliensis strains could be distinguished from other bacterial mEVs. Additionally, one combination of antibodies used in a sandwich assay could distinguish Fournierella massiliensis Strain A (ATCC Deposit Number PTA-126696) (also referred to herein as “F. massiliensis 1”) and another Fournierella massiliensis strain (also referred to herein as “F. massiliensis 2”) from mEVs from another genus based on particle count. [0059] In other aspects, provided herein are methods of using the antibodies disclosed herein to purify bacteria and/or mEVs form solution, for example, from a fermentation solution or another in-process solution. Definitions [0060] Unless specifically stated or obvious from context, as used herein, the terms "a," "an," and "the" are understood to be singular or plural. [0061] As used herein, the term “antibody” may refer to both an intact antibody and an antigen binding fragment thereof. Intact antibodies are glycoproteins that include at least two heavy (H) chains and two light (L) chains inter-connected by disulfide bonds. Each heavy chain includes a heavy chain variable region (abbreviated herein as VH) and a heavy chain constant region. Each light chain includes a light chain variable region (abbreviated herein as V_L) and a light chain constant region. The V_H and V_L regions can be further subdivided into regions of hypervariability, termed complementarity determining regions (CDR), interspersed with regions that are more conserved, termed framework regions (FR). Each V_H and V_L is composed of three CDRs and four FRs, arranged from amino-terminus to carboxy-terminus in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4. As used herein, CDRH1, CDRH2, and CDRH3 respectively refer to CDR1, CDR2 and CDR3 of the heavy chain, while CDRL1, CDRL2, and CDRL3 respectively refer to CDR1, CDR2 and CDR3 of the light chain. The variable regions of the heavy and light chains contain a binding domain that interacts with an antigen. The term “antibody” includes, for example, monoclonal antibodies, polyclonal antibodies, chimeric antibodies, humanized antibodies, human antibodies, multispecific antibodies (e.g., bispecific antibodies), single-chain antibodies and antigen-binding antibody fragments. [0062] An “antigen,” as used herein, refers to a molecule that is specifically recognized by an antibody. In some embodiments, an antigen is a surface molecule. [0063] The terms “antigen binding fragment” and “antigen-binding portion” of an antibody, as used herein, refer to one or more fragments of an antibody that retain the ability to bind to an antigen. Examples of binding fragments encompassed within the term "antigen-binding fragment" of an antibody include Fab, Fab', F(ab')2, Fv, scFv, disulfide linked Fv, Fd, diabodies, single-chain antibodies, NANOBODIES®, isolated CDRH3, and other antibody fragments that retain at least a portion of the variable region of an intact antibody. These antibody fragments can be obtained and/or derived using conventional recombinant and/or enzymatic techniques and can be screened for antigen binding in the same manner as intact antibodies. [0064] The term “drug substance” as used herein refers to a pharmaceutical agent comprising bacteria and/or microbial extracellular vesicles (mEVs) (such as smEVs and/or pmEVs). For example, the drug substances (e.g., pharmaceutical agent) disclosed herein may be a powder comprising bacteria and/or microbial extracellular vesicles (mEVs) (such as smEVs and/or pmEVs). In some embodiments, the drug substances may further comprise an excipient. The term “drug product” as used herein refers to a pharmaceutical composition comprising a pharmaceutical agent. For example, the pharmaceutical composition may be a tablet comprising the pharmaceutical agent. In some embodiments, the pharmaceutical composition may be a powder comprising the pharmaceutical agent and additional excipients. [0065] The term “epitope” means a protein determinant capable of specific binding to an antibody or T cell receptor. Epitopes usually consist of chemically active surface groupings of molecules such as amino acids or sugar side chains. Certain epitopes can be defined by a particular sequence of amino acids to which an antibody is capable of binding. [0066] The term “binds to the same epitope” with reference to two or more antibodies means that the antibodies bind to the same segment of amino acid residues, as determined by a given method. Techniques for determining whether antibodies bind to the "same epitope on ENPP1" with the antibodies described herein include, for example, epitope mapping methods, such as, x-ray analyses of crystals of antigen:antibody complexes which provides atomic resolution of the epitope and hydrogen/deuterium exchange mass spectrometry (HDX-MS). Other methods monitor the binding of the antibody to antigen fragments or mutated variations of the antigen where loss of binding due to a modification of an amino acid residue within the antigen sequence is often considered an indication of an epitope component. In addition, computational combinatorial methods for epitope mapping can also be used. These methods rely on the ability of the antibody of interest to affinity isolate specific short peptides from combinatorial phage display peptide libraries. Antibodies having the same V_H and V_L or the same CDR1, 2 and 3 sequences are expected to bind to the same epitope. [0067] “Identity” between two sequences is a function of the number of identical positions shared by the sequences (i.e., % homology = # of identical positions/total # of positions x 100), taking into account the number of gaps, and the length of each gap, which need to be introduced for optimal alignment of the two sequences. [0068] The term “increase” means a change, such that the difference is, depending on circumstances, at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 2-fold, 4- fold, 10-fold, 100-fold, 10^3 fold, 10^4 fold, 10^5 fold, 10^6 fold, and/or 10^7 fold greater after treatment with an agent (e.g. mEVs) when compared to a pre-treatment state. Properties that may be increased include the number of immune cells, bacterial cells, stromal cells, myeloid obtained and/or derived suppressor cells, fibroblasts, metabolites; the level of a cytokine; or another physical parameter (such as ear thickness (e.g., in a DTH animal model) or tumor size). [0069] The terms “isolated”, “purified,” or “enriched” encompasses a microbe (such as a bacterium), mEV (such as an smEV and/or pmEV), or other entity or substance that has been (1) separated from at least some of the components with which it was associated when initially produced (whether in nature or in an experimental setting), and/or (2) produced, prepared, purified, and/or manufactured by the hand of man. Isolated microbes or mEVs may be separated from at least about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, or more of the other components with which they were initially associated. In some embodiments, isolated microbes or mEVs are more than about 80%, about 85%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, about 99%, or more than about 99% pure. As used herein, a substance is “pure” if it is substantially free of other components. The terms “purify,” “purifying” and “purified” refer to a microbe or other material that has been separated from at least some of the components with which it was associated either when initially produced or generated (e.g., whether in nature or in an experimental setting), or during any time after its initial production. A microbe or a microbial population or mEVs may be considered purified if it is isolated at or after production, such as from a material or environment containing the microbe or microbial population, and a purified microbe or microbial population may contain other materials up to about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, or above about 90% and still be considered “isolated.” In some embodiments, purified microbes or microbial population or mEVs are more than about 80%, about 85%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, about 99%, or more than about 99% pure. In the instance of microbial compositions provided herein, the one or more microbial types present in the composition can be independently purified from one or more other microbes produced and/or present in the material or environment containing the microbial type. Microbial compositions and the microbial components thereof are generally purified from residual habitat products. [0070] In certain embodiments, the antibodies provided herein can be of any isotype. As used herein, "isotype" refers to the antibody class (e.g., IgG1, IgG2, IgG3, IgG4, IgM, IgA1, IgA2, IgD, and IgE) that is encoded by the heavy chain constant region genes. In some embodiments, the antibodies provided herein are IgG isotype antibodies (IgG1, IgG2, IgG3 and IgG4 in humans, and IgG1, IgG2a, IgG2b and IgG3 in mice). [0071] “Microbial extracellular vesicles” (mEVs) can be obtained and/or derived from microbes such as bacteria, archaea, fungi, microscopic algae, protozoans, and parasites. In some embodiments, the mEVs are obtained and/or derived from bacteria. In a preferred embodiment, a purified mEV composition may be substantially free of its originating or associated microbe (e.g., bacteria). mEVs include secreted microbial extracellular vesicles (smEVs) and processed microbial extracellular vesicles (pmEVs). “Secreted microbial extracellular vesicles” (smEVs) are vesicles naturally produced by microbes. smEVs are comprised of microbial lipids and/or microbial proteins and/or microbial nucleic acids and/or microbial carbohydrate moieties, and are isolated from culture supernatant. The natural production of these vesicles can be artificially enhanced (e.g., increased) or decreased through manipulation of the environment in which the bacterial cells are being cultured (e.g., by media or temperature alterations). Further, smEV compositions may be modified to reduce, increase, add, or remove microbial components or foreign substances to alter efficacy, immune stimulation, stability, immune stimulatory capacity, stability, organ targeting (e.g., lymph node), absorption (e.g., gastrointestinal), and/or yield (e.g., thereby altering the efficacy). As used herein, the term “purified smEV composition” or “smEV composition” refers to a preparation of smEVs that have been separated from at least one associated substance found in a source material (e.g., separated from at least one other microbial component) or any material associated with the smEVs in any process used to produce the preparation. It can also refer to a composition that has been significantly enriched for specific components. In a preferred embodiment, a purified smEV composition may be substantially free of its originating or associated microbe (e.g., bacteria). “Processed microbial extracellular vesicles” (pmEVs) are a non-naturally- occurring collection of microbial membrane components that have been purified from artificially lysed microbes (e.g., bacteria) (e.g., microbial membrane components that have been separated from other, intracellular microbial cell components), and which may comprise particles of a varied or a selected size range, depending on the method of purification. A pool of pmEVs is obtained and/or derived by chemically disrupting (e.g., by lysozyme and/or lysostaphin) and/or physically disrupting (e.g., by mechanical force) microbial cells and separating the microbial membrane components from the intracellular components through centrifugation and/or ultracentrifugation, or other methods. The resulting pmEV mixture contains an enrichment of the microbial membranes and the components thereof (e.g., peripherally associated or integral membrane proteins, lipids, glycans, polysaccharides, carbohydrates, other polymers), such that there is an increased concentration of microbial membrane components, and a decreased concentration (e.g., dilution) of intracellular contents, relative to whole microbes. For gram-positive bacteria, pmEVs may include cell or cytoplasmic membranes. For gram-negative bacteria, a pmEV may include inner and outer membranes. pmEVs may be modified to increase purity, to adjust the size of particles in the composition, and/or modified to reduce, increase, add or remove, microbial components or foreign substances to alter efficacy, immune stimulation, stability, immune stimulatory capacity, stability, organ targeting (e.g., lymph node), absorption (e.g., gastrointestinal), and/or yield (e.g., thereby altering the efficacy). pmEVs can be modified by adding, removing, enriching for, or diluting specific components, including intracellular components from the same or other microbes. As used herein, the term “purified pmEV composition” or “pmEV composition” refers to a preparation of pmEVs that have been separated from at least one associated substance found in a source material (e.g., separated from at least one other microbial component) or any material associated with the pmEVs in any process used to produce the preparation. It can also refer to a composition that has been significantly enriched for specific components. In a preferred embodiment, a purified pmEV composition may be substantially free of its originating or associated whole microbe (e.g., bacteria). Extracellular vesicles (smEVs and/or pmEVs) may also be obtained from mammalian cells. The methods provided herein may be used with mammalian cells or extracellular vesicles obtained and/or derived from mammaliam cells. Extracellular vesicles (smEVs and/or pmEVs) may also be obtained and/or derived from a microbe, e.g., a microbe that is an archaea, fungi, microscopic algae, protozoan, or parasite. The methods provided herein may be used with microbial cells or extracellular vesicles obtained and/or derived from microbial cells, e.g., where the microbial cells are cells of an archaea, fungi, microscopic algae, protozoan, or parasite. [0072] In some embodiments, the antibodies provided herein are monoclonal antibodies. The term “monoclonal antibody,” as used herein, refers to an antibody that displays a single binding specificity and affinity for a particular epitope or a composition of antibodies in which all antibodies display a single binding specificity and affinity for a particular epitope. Accordingly, the term “human monoclonal antibody” refers to an antibody or antibody composition that display(s) a single binding specificity and which has variable and optional constant regions obtained and/or derived from human germline immunoglobulin sequences. In one embodiment, human monoclonal antibodies are produced by a hybridoma which includes a B cell obtained and/or derived from a transgenic non-human animal, e.g., a transgenic mouse, having a genome comprising a human heavy chain transgene and a light chain transgene fused to an immortalized cell. [0073] The terms “polynucleotide”, and “nucleic acid” are used interchangeably. They refer to a polymeric form of nucleotides of any length, either deoxyribonucleotides or ribonucleotides, or mixtures (e.g., containing both deoxyribonucleotides and ribonucleotides) or analogs thereof. Polynucleotides may have any three-dimensional structure and may perform any function. For example, polynucleotides may form intramolecular (e.g., hairpin) or intermolecular (e.g., duplex) structures. The following are non-limiting examples of polynucleotides: coding or non-coding regions of a gene or gene fragment, loci (locus) defined from linkage analysis, exons, introns, messenger RNA (mRNA), micro RNA (miRNA), silencing RNA (siRNA), transfer RNA, ribosomal RNA, ribozymes, cDNA, recombinant polynucleotides, branched polynucleotides, plasmids, vectors, isolated DNA of any sequence, isolated RNA of any sequence, nucleic acid probes, and primers. A polynucleotide may comprise modified nucleotides, such as methylated nucleotides and nucleotide analogs. If present, modifications to the nucleotide structure may be imparted before or after assembly of the polymer. A polynucleotide may be further modified, such as by conjugation with a labeling component. In all nucleic acid sequences provided herein, U nucleotides are interchangeable with T nucleotides. [0074] As used herein, “specific binding” refers to the ability of an antibody to bind to a predetermined antigen or the ability of a polypeptide to bind to its predetermined binding partner. Typically, an antibody or polypeptide specifically binds to its predetermined antigen or binding partner with an affinity corresponding to a KD of about 10^-7 M or less, and binds to the predetermined antigen/binding partner with an affinity (as expressed by K_D) that is at least 10 fold less, at least 100 fold less or at least 1000 fold less than its affinity for binding to a non-specific and unrelated antigen/binding partner (e.g., BSA, casein). Alternatively, specific binding applies more broadly to a two-component system where one component is a protein, lipid, or carbohydrate or combination thereof and engages with the second component which is a protein, lipid, carbohydrate or combination thereof in a specific way. [0075] “Strain” refers to a member of a bacterial species with a genetic signature such that it may be differentiated from closely-related members of the same bacterial species. The genetic signature may be the absence of all or part of at least one gene, the absence of all or part of at least one regulatory region (e.g., a promoter, a terminator, a riboswitch, a ribosome binding site), the absence (“curing”) of at least one native plasmid, the presence of at least one recombinant gene, the presence of at least one mutated gene, the presence of at least one foreign gene (a gene obtained and/or derived from another species), the presence at least one mutated regulatory region (e.g., a promoter, a terminator, a riboswitch, a ribosome binding site), the presence of at least one non-native plasmid, the presence of at least one antibiotic resistance cassette, or a combination thereof. Genetic signatures between different strains may be identified by PCR amplification optionally followed by DNA sequencing of the genomic region(s) of interest or of the whole genome. In the case in which one strain (compared with another of the same species) has gained or lost antibiotic resistance or gained or lost a biosynthetic capability (such as an auxotrophic strain), strains may be differentiated by selection or counter-selection using an antibiotic or nutrient/metabolite, respectively. [0076] As used herein, a "type" of bacteria may be distinguished from other bacteria by: genus, species, sub-species, strain or by any other taxonomic categorization, whether based on morphology, physiology, genotype, protein expression or other characteristics known in the art. Antibodies [0077] In certain aspects, provided herein are antibodies and antigen binding fragments thereof. In some embodiments, the antibody or antigen binding fragment thereof comprises one or more (e.g., 1, 2, 3, 4, 5, or 6) heavy or light chain CDR sequences set forth in Table 1. In certain embodiments, the antibody or antigen binding fragment thereof comprises a heavy chain variable region sequence set forth in Table 1. In certain embodiments, the antibody or antigen binding fragment thereof comprises a light chain variable region sequence set forth in Table 1. In some embodiments, the antibody comprises a heavy chain sequence set forth in Table 1. In some embodiments, the antibody comprises a light chain sequence set forth in Table 1. [0078] In some embodiments, the antibody comprises a heavy chain CDR3 of SEQ ID NO: 5. In certain embodiments, the antibody further comprises a heavy chain CDR1 of SEQ ID NO: 3 and a heavy chain CDR2 of SEQ ID NO: 4. In some embodiments, the antibody comprises a heavy chain variable region having a sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to SEQ ID NO: 2. In some embodiments, the antibody comprises a heavy chain variable region of SEQ ID NO: 2. In some embodiments, the antibody comprises a heavy chain having a sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to SEQ ID NO: 1. In some embodiments, the antibody comprises a heavy chain of SEQ ID NO: 1. In some embodiments, the antibody comprises a light chain CDR3 of SEQ ID NO: 10. In certain embodiments, the antibody comprises a light chain CDR1 of SEQ ID NO: 8 and a light chain CDR2 of SEQ ID NO: 9. In some embodiments, the antibody comprises a light chain variable region having a sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to SEQ ID NO: 7. In some embodiments, the antibody comprises a light chain variable region of SEQ ID NO: 7. In some embodiments, the antibody comprises a light chain having a sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to SEQ ID NO: 6. In certain embodiments, the antibody comprises a light chain of SEQ ID NO: 6. [0079] In some embodiments, the antibody comprises a heavy chain CDR3 of SEQ ID NO: 15. In certain embodiments, the antibody further comprises a heavy chain CDR1 of SEQ ID NO: 13 and a heavy chain CDR2 of SEQ ID NO: 14. In some embodiments, the antibody comprises a heavy chain variable region having a sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to SEQ ID NO: 12. In some embodiments, the antibody comprises a heavy chain variable region of SEQ ID NO: 12. In some embodiments, the antibody comprises a heavy chain having a sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to SEQ ID NO: 11. In some embodiments, the antibody comprises a heavy chain of SEQ ID NO: 11. In some embodiments, the antibody comprises a light chain CDR3 of SEQ ID NO: 20. In certain embodiments, the antibody comprises a light chain CDR1 of SEQ ID NO: 18 and a light chain CDR2 of SEQ ID NO: 19. In some embodiments, the antibody comprises a light chain variable region having a sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to SEQ ID NO: 17. In some embodiments, the antibody comprises a light chain variable region of SEQ ID NO: 17. In some embodiments, the antibody comprises a light chain having a sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to SEQ ID NO: 16. In certain embodiments, the antibody comprises a light chain of SEQ ID NO: 16. [0080] In certain embodiments, the antibody or antigen binding fragment thereof provided herein binds to mEVs obtained and/or derived from bacteria of the genus Prevotella (e.g., bacteria of the species Prevotella histicola, such as bacteria of the strain Prevotella Strain B 50329). In some embodiments, the antibody or antigen binding fragment thereof provided herein binds to bacteria of the genus Prevotella (e.g., bacteria of the species Prevotella histicola, such as bacteria of the strain Prevotella Strain B 50329). In some embodiments, the antibody provided herein competes for antigen binding with an antibody having a heavy chain sequence of SEQ ID NO: 1 and a light chain sequence of SEQ ID NO: 6. In some embodiments, the antibody provided herein competes for antigen binding with an antibody having a heavy chain sequence of SEQ ID NO: 11 and a light chain sequence of SEQ ID NO: 16. In some embodiments, the antibody provided herein competes for antigen binding with an antibody having a heavy chain variable region sequence of SEQ ID NO: 2 and a light chain variable region sequence of SEQ ID NO: 7. In some embodiments, the antibody provided herein competes for antigen binding with an antibody having a heavy chain variable region sequence of SEQ ID NO: 12 and a light chain variable region sequence of SEQ ID NO: 17. [0081] In some embodiments provided herein, the antibody or antigen binding fragment thereof binds to mEVs obtained and/or derived from bacteria of the genus Fournierella (e.g., bacteria of the species Fournierella massiliensis, such as bacteria of the strain Fournierella massiliensis Strain A (ATCC Deposit Number PTA-126696)). In some embodiments provided herein, the antibody or antigen binding fragment thereof binds to bacteria of the genus Fournierella (e.g., bacteria of the species Fournierella massiliensis, such as bacteria of the strain Fournierella massiliensis Strain A (ATCC Deposit Number PTA-126696)). [0082] As reported herein, antibodies that specifically bind a marker (e.g., antigen or epitope) (e.g., of an extracellular vesicle or a particular bacterial protein or other biomolecule (e.g., carbohydrate, lipid, or the like)) are useful in the methods provided herein, including methods for detecting and/or quantifying mEVs from particular bacterial species and/or strains. In particular embodiments, provided herein are methods for detecting and/or quantifying the presence of an mEV from a particular bacterial strain by contacting the mEV with a first antibody (e.g., a capture antibody) and then contacting with a second antibody (a detection antibody). In some embodiments, the first antibody is a detection antibody and the second antibody is a capture antibody. [0083] Antibodies typically bind specifically to their cognate antigen with high affinity, reflected by a dissociation constant (KD) of 10^-5 to 10^-11 M or less. Any KD greater than about 10^-4 M is generally considered to indicate nonspecific binding. As used herein, an antibody that "binds specifically" to an antigen refers to an antibody that binds to the antigen and substantially identical antigens with high affinity, which means having a KD of 10^-7 M or less, preferably 10^-8 M or less, even more preferably 5 x 10^-9 M or less, and most preferably between 10^-8 M and 10^-10 M or less, but does not bind with high affinity to unrelated antigens. An antigen is "substantially identical" to a given antigen if it exhibits a high degree of sequence identity to the given antigen, for example, if it exhibits at least 80%, at least 90%, preferably at least 95%, more preferably at least 97%, or even more preferably at least 99% sequence identity to the sequence of the given antigen. [0084] In certain embodiments, provided herein are antigen-binding fragments of antibodies disclosed herein. The term “antigen-binding fragment” of an antibody, as used herein, refers to one or more fragments of an antibody that retain the ability to specifically bind to an antigen. It has been shown that the antigen-binding function of an antibody can be performed by fragments of a full-length antibody. Examples of binding fragments encompassed within the term “antigen-binding fragment” of an antibody, described herein, include (i) a Fab fragment, a monovalent fragment consisting of the VL, VH, CL and CH1 domains; (ii) a F(ab')2 fragment, a bivalent fragment comprising two Fab fragments linked by a disulfide bridge at the hinge region; (iii) a Fd fragment consisting of the V_H and CH1 domains; (iv) a Fv fragment consisting of the VL and VH domains of a single arm of an antibody, (v) a dAb fragment (Ward et al., (1989) Nature 341:544-546), which consists of a V_H domain; and (vi) an isolated complementarity determining region (CDR) or (vii) a combination of two or more isolated CDRs which may optionally be joined by a synthetic linker. Furthermore, although the two domains of the Fv fragment, VL and VH, are coded for by separate genes, they can be joined, using recombinant methods, by a synthetic linker that enables them to be made as a single protein chain in which the V_L and V_H regions pair to form monovalent molecules (known as single chain Fv (scFv); see e.g., Bird et al. (1988) Science 242:423-426; and Huston et al. (1988) Proc. Natl. Acad. Sci. USA 85:5879-5883). Such single chain antibodies are also intended to be encompassed within the term “antigen- binding fragment” of an antibody. These antibody fragments are obtained and/or derived using conventional techniques known to those with skill in the art, and the fragments are screened for utility in the same manner as are intact antibodies. Antigen-binding fragments can be produced by recombinant DNA techniques, or by enzymatic or chemical cleavage of intact immunoglobulins. [0085] In certain embodiments, the antibodies provided herein comprise one or more CDRs (e.g., as provided in Table 1). “CDRs” of an antibody are amino acid residues within the hypervariable region that are identified in accordance with the definitions of the Kabat, Chothia, AbM, contact, and/or conformational definitions or any method of CDR determination well known in the art. Antibody CDRs may be identified as the hypervariable regions originally defined by Kabat et al. See, e.g., Kabat et al., 1992, Sequences of Proteins of Immunological Interest, 5th ed., Public Health Service, NIH, Washington D.C. The positions of the CDRs may also be identified as the structural loop structures originally described by Chothia and others. See, e.g., Chothia et al., 1989, Nature 342:877-883. Other approaches to CDR identification include the “AbM definition,” which is a compromise between Kabat and Chothia and is obtained using Oxford Molecular's AbM antibody modeling software (now Accelrys®), or the “contact definition” of CDRs based on observed antigen contacts, set forth in MacCallum et al., 1996, J. Mol. Biol., 262:732-745. In another approach, referred to herein as the “conformational definition” of CDRs, the positions of the CDRs may be identified as the residues that make enthalpic contributions to antigen binding. See, e.g., Makabe et al., 2008, Journal of Biological Chemistry, 283:1156- 1166. Still other CDR boundary definitions may not strictly follow one of the above approaches, but will nonetheless overlap with at least a portion of the Kabat CDRs, although they may be shortened or lengthened in light of prediction or experimental findings that particular residues or groups of residues or even entire CDRs do not significantly impact antigen binding. As used herein, a CDR may refer to CDRs defined by any approach known in the art, including combinations of approaches. The methods used herein may utilize CDRs defined according to any of these approaches. For any given embodiment containing more than one CDR, the CDRs may be defined in accordance with any of Kabat, Chothia, extended, AbM, contact, and/or conformational definitions. [0086] In some embodiments, the antibodies provided herein are monoclonal antibodies. The term “monoclonal antibody,” as used herein, refers to an antibody that displays a single binding specificity and affinity for a particular epitope or a composition of antibodies in which all antibodies display a single binding specificity and affinity for a particular epitope. [0087] In certain embodiments, provided herein are antibodies that compete with an antibody provided herein for antigen binding. Antibodies that “compete with another antibody for binding to an antigen” refer to antibodies that inhibit (partially or completely) the binding of the other antibody to a target protein. Whether two antibodies compete with each other for binding to a target, i.e., whether and to what extent one antibody inhibits the binding of the other antibody to a target, may be determined using known competition experiments. In certain embodiments, an antibody competes with, and inhibits binding of another antibody to a target by at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or 100%. The level of inhibition or competition may be different depending on which antibody is the “blocking antibody” (i.e., the cold antibody that is incubated first with the target). Competition assays can be conducted as described, for example, in Ed Harlow and David Lane, Cold Spring Harb Protoc ; 2006; doi:10.1101/pdb.prot4277 or in Chapter 11 of “Using Antibodies” by Ed Harlow and David Lane, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY, USA 1999. Competing antibodies bind to the same epitope, an overlapping epitope or to adjacent epitopes (e.g., as evidenced by steric hindrance). [0088] Other competitive binding assays include: solid phase direct or indirect radioimmunoassay (RIA), solid phase direct or indirect enzyme immunoassay (EIA), sandwich competition assay (see Stahli et al., Methods in Enzymology 9:242 (1983)); solid phase direct biotin-avidin EIA (see Kirkland et al., J. Immunol.137:3614 (1986)); solid phase direct labeled assay, solid phase direct labeled sandwich assay (see Harlow and Lane, Antibodies: A Laboratory Manual, Cold Spring Harbor Press (1988)); solid phase direct label RIA using I-125 label (see Morel et al., Mol. Immunol.25(1):7 (1988)); solid phase direct biotin-avidin EIA (Cheung et al., Virology 176:546 (1990)); and direct labeled RIA. (Moldenhauer et al., Scand. J. Immunol.32:77 (1990)). [0089] As used herein, the terms “specific binding,” “selective binding,” “selectively binds,” and “specifically binds,” refer to antibody binding to an epitope on a predetermined antigen. Typically, the antibody (i) binds with an equilibrium dissociation ^{constant (K} _D ^{) of approximately less than 10-7 M, such as approximately less than 10 -8 M,} 10^-9 M or 10^-10 M or even lower when determined by, e.g., surface plasmon resonance (SPR) technology in a BIACORE 2000 instrument using the predetermined antigen, as the analyte and the antibody as the ligand, or Scatchard analysis of binding of the antibody to antigen positive cells, and (ii) binds to the predetermined antigen with an affinity that is at least two-fold greater than its affinity for binding to a non-specific antigen (e.g., BSA, casein) other than the predetermined antigen or a closely-related antigen. [0090] In certain aspects, provided herein are nucleic acid molecules encoding an antibody provided herein. The term “nucleic acid molecule,” as used herein, is intended to include DNA molecules and RNA molecules. A nucleic acid molecule may be single- stranded or double-stranded, and may be cDNA. [0091] Also provided are antibodies having “conservative sequence modifications” of the sequences set forth herein, e.g., in Table 1, i.e., amino acid sequence modifications which do not abrogate the binding of the antibody to the antigen. Such conservative sequence modifications include conservative amino acid substitutions. For example, modifications can be introduced into a sequence by standard techniques known in the art, such as site-directed mutagenesis and PCR-mediated mutagenesis. Conservative amino acid substitutions include ones in which the amino acid residue is replaced with an amino acid residue having a similar side chain. Families of amino acid residues having similar side chains have been defined in the art. These families include amino acids with basic side chains (e.g., lysine, arginine, histidine), acidic side chains (e.g., aspartic acid, glutamic acid), uncharged polar side chains (e.g., glycine, asparagine, glutamine, serine, threonine, tyrosine, cysteine, tryptophan), nonpolar side chains (e.g., alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine), beta-branched side chains (e.g., threonine, valine, isoleucine) and aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan, histidine). Thus, an amino acid residue in an antibody provided herein is preferably replaced with another amino acid residue from the same side chain family. Methods of identifying nucleotide and amino acid conservative substitutions which do not eliminate antigen binding are well-known in the art (see, e.g., Brummell et al., Biochem.32:1180- 1187 (1993); Kobayashi et al. Protein Eng.12(10):879-884 (1999); and Burks et al. Proc. Natl. Acad. Sci. USA 94:412-417 (1997)). [0092] In some embodiments, provided herein are vectors encoding the heavy and/or light chain of an antibody provided herein. The term “vector”, as used herein, is intended to refer to a nucleic acid molecule capable of transporting another nucleic acid to which it has been linked. One type of vector is a “plasmid,” which refers to a circular double stranded DNA loop into which additional DNA segments may be ligated. Another type of vector is a viral vector, wherein additional DNA segments may be ligated into the viral genome. Certain vectors are capable of autonomous replication in a host cell into which they are introduced (e.g., bacterial vectors having a bacterial origin of replication and episomal mammalian vectors). Other vectors (e.g., non-episomal mammalian vectors) can be integrated into the genome of a host cell upon introduction into the host cell, and thereby are replicated along with the host genome. Moreover, certain vectors are capable of directing the expression of genes to which they are operatively linked. Such vectors are referred to herein as “recombinant expression vectors” (or simply, “expression vectors”). In general, expression vectors of utility in recombinant DNA techniques are often in the form of plasmids. In the present specification, “plasmid” and “vector” may be used interchangeably as the plasmid is the most commonly used form of vector. However, also included are other forms of expression vectors, such as viral vectors (e.g., replication defective retroviruses, adenoviruses and adeno-associated viruses), which serve equivalent functions. [0093] In some embodiments, provided herein is a host cell comprising a nucleic acid molecule that encodes an amino acid sequence disclosed herein. The term “recombinant host cell” (or simply “host cell”), as used herein, is intended to refer to a cell that comprises a nucleic acid that is not naturally present in the cell, and maybe a cell into which a recombinant expression vector has been introduced. It should be understood that such terms are intended to refer not only to the particular subject cell but to the progeny of such a cell. Because certain modifications may occur in succeeding generations due to either mutation or environmental influences, such progeny may not, in fact, be identical to the parent cell, but are still included within the scope of the term “host cell” as used herein. [0094] In certain embodiments, the antibodies provided herein are detectably labeled. Examples of detectable labels include, but are not limited to, fluorescent moieties, radioactive moieties, paramagnetic moieties, luminescent moieties and/or colorimetric moieties. In some embodiments, the targets described herein are linked to, comprise and/or are bound by a fluorescent moiety. Examples of fluorescent moieties include, but are not limited to, Allophycocyanin, Fluorescein, Phycoerythrin, Peridinin-chlorophyll protein complex, Alexa Fluor 350, Alexa Fluor 405, Alexa Fluor 430, Alexa Fluor 488, Alexa Fluor 514, Alexa Fluor 532, Alexa Fluor 546, Alexa Fluor 555, Alexa Fluor 568, Alexa Fluor 594, Alexa Fluor 633, Alexa Fluor 635, Alexa Fluor 647, Alexa Fluor 660, Alexa Fluor 680, Alexa Fluor 700, Alexa Fluor 750, Alexa Fluor 790, EGFP, mPlum, mCherry, mOrange, mKO, EYFP, mCitrine, Venus, YPet, Emerald, Cerulean and CyPet. [0095] In some embodiments, the antibody is biotinylated. [0096] In certain embodiments, the antibodies provided herein are immobilized on a solid support. Examples of solid supports include, but are not limited to, biochips, microwells, beads, columns, flow cells, and membranes. In some embodiments, the solid support may be any one of, but are not limited to, the following: biochips, microwells, beads, columns, flow cells, and membranes. In some embodiments, the solid support is a bead. In some embodiments, the bead is a latex bead. In some embodiments, the bead is a magnetic bead. In some embodiments, the bead is an agarose bead. In some embodiments, the solid support is a column. In some embodiments, the column is any one of, but are not limited to, the following: protein A, protein G column, streptavidin column, spin-column, and resin columns. Bacteria and mEVs [0097] In certain embodiments, the methods and compositions provided herein can be used to analyze and/or detect and/or quantify any type of bacteria or bacterial mEVs. As used herein, a "type" of bacteria may be distinguished from other bacteria by: genus, species, sub-species, strain or by any other taxonomic categorization, whether based on morphology, physiology, genotype, protein expression or other characteristics known in the art. [0098] Examples of taxonomic groups (e.g., class, order, family, genus, species or strain) of bacteria that can be used as a source of bacteria and/or mEVs (such as smEVs and/or pmEVs) are provided herein (e.g., listed in Table 2, Table 3, Table 4, and/or Table 5). Antibodies binding to any bacterial strains provided herein, or from which mEVs are obtained and/or derived (bacterial mEVs), may be produced and used in a method described herein to detect, identify, and/or quantify the bacteria or bacterial mEVs. [0099] In some embodiments, the bacterial strain is a bacterial strain having a genome that has at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8% or 99.9% sequence identity to a strain listed herein. [0100] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are oncotrophic bacteria. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are immunomodulatory bacteria. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are immunostimulatory bacteria. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are immunosuppressive bacteria. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are immunomodulatory bacteria. In certain embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are generated from a combination of bacterial strains provided herein. In some embodiments, the combination is a combination of at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, 30, 35, 40, 45 or 50 bacterial strains. In some embodiments, the combination includes the bacteria or the bacteria from which the mEVs are obtained and/or derived (e.g., bacterial strains listed herein and/or bacterial strains having a genome that has at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8% or 99.9% sequence identity to a strain listed herein (e.g., listed in Table 2, Table 3, Table 4, and/or Table 5). In certain embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are generated from a bacterial strain provided herein. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are from a bacterial strain listed herein (e.g., listed in Table 2, Table 3, Table 4, and/or Table 5) and/or a bacterial strain having a genome that has at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8% or 99.9% sequence identity to a strain listed herein (e.g., listed in Table 2, Table 3, Table 4, and/or Table 5). [0101] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are gram-negative bacteria. [0102] In some embodiments, the gram-negative bacteria belong to the class Negativicutes. The Negativicutes represent a unique class of microorganisms as they are the only diderm members of the Firmicutes phylum. These anaerobic organisms can be found in the environment and are normal commensals of the oral cavity and GI tract of humans. Because these organisms have an outer membrane, the yields of mEVs from this class were investigated. It was found that on a per cell basis these bacteria produce a high number of vesicles (10-150 mEVs/cell). The mEVs from these organisms are broadly stimulatory and highly potent in in vitro assays. Investigations into their therapeutic applications in several oncology and inflammation in vivo models have shown their therapeutic potential. The Negativicutes class includes the families Veillonellaceae, Selenomonadaceae, Acidaminococcaceae, and Sporomusaceae. The Negativicutes class includes the genera Megasphaera, Selenomonas, Propionospora, and Acidaminococcus. Exemplary Negativicutes species include, but are not limited to, Megasphaera sp., Selenomonas felix, Acidaminococcus intestine, and Propionospora sp. [0103] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are gram-positive bacteria. [0104] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are aerobic bacteria. [0105] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are anaerobic bacteria. In some embodiments, the anaerobic bacteria comprise obligate anaerobes. In some embodiments, the anaerobic bacteria comprise facultative anaerobes. [0106] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are acidophile bacteria. [0107] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are alkaliphile bacteria. [0108] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are neutralophile bacteria. [0109] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are fastidious bacteria. [0110] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are nonfastidious bacteria. [0111] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived or the mEVs themselves are lyophilized. [0112] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived or the mEVs themselves are gamma irradiated (e.g., at 17.5 or 25 kGy). [0113] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived or the mEVs themselves are UV irradiated. [0114] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived or the mEVs themselves are heat inactivated (e.g., at 50°C for two hours or at 90°C for two hours). [0115] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived or the mEVs themselves are acid treated. [0116] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived or the mEVs themselves are oxygen sparged (e.g., at 0.1 vvm for two hours). [0117] The phase of growth can affect the amount or properties of bacteria and/or mEVs produced by bacteria. For example, mEVs can be isolated, e.g., from a culture, at the start of the log phase of growth, midway through the log phase, and/or once stationary phase growth has been reached. [0118] In certain embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived from obligate anaerobic bacteria. Examples of obligate anaerobic bacteria include gram-negative rods (including the genera of Bacteroides, Prevotella, Porphyromonas, Fusobacterium, Bilophila, and Sutterella spp.), gram-positive cocci (primarily Peptostreptococcus spp.), gram-positive spore-forming (Clostridium spp.), non-spore-forming bacilli (Actinomyces, Propionibacterium, Eubacterium, Lactobacillus and Bifidobacterium spp.), and gram-negative cocci (mainly Veillonella spp.). In some embodiments, the obligate anaerobic bacteria are of a genus selected from the group consisting of Agathobaculum, Atopobium, Blautia, Burkholderia, Dielma, Longicatena, Paraclostridium, Turicibacter, and Tyzzerella. [0119] The Negativicutes class includes the families Veillonellaceae, Selenomonadaceae, Acidaminococcaceae, and Sporomusaceae. The Negativicutes class includes the genera Megasphaera, Selenomonas, Propionospora, and Acidaminococcus. Exemplary Negativicutes species include, but are not limited to, Megasphaera sp., Selenomonas felix, Acidaminococcus intestini, and Propionospora sp. [0120] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Negativicutes class. [0121] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Veillonellaceae family. [0122] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Selenomonadaceae family. [0123] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Acidaminococcaceae family. [0124] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Sporomusaceae family. [0125] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Megasphaera genus. [0126] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Selenomonas genus. [0127] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Propionospora genus. [0128] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Acidaminococcus genus. [0129] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Megasphaera sp. bacteria. [0130] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Selenomonas felix bacteria. [0131] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Acidaminococcus intestini bacteria. [0132] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Propionospora sp. bacteria. [0133] The Oscillospiraceae family within the Clostridia class of microorganisms are common commensal organisms of vertebrates. [0134] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Clostridia class. [0135] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Oscillospiraceae family. [0136] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Faecalibacterium genus. [0137] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Fournierella genus. [0138] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Harryflintia genus. [0139] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Agathobaculum genus. [0140] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Faecalibacterium prausnitzii (e.g., Faecalibacterium prausnitzii Strain A) bacteria. [0141] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Fournierella massiliensis (e.g., Fournierella massiliensis Strain A) bacteria. [0142] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Harryflintia acetispora (e.g., Harryflintia acetispora Strain A) bacteria. [0143] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Agathobaculum sp. (e.g., Agathobaculum sp. Strain A) bacteria. [0144] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are bacteria of a genus selected from the group consisting of Escherichia, Klebsiella, Lactobacillus, Shigella, and Staphylococcus. [0145] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are a species selected from the group consisting of Blautia massiliensis, Paraclostridium benzoelyticum, Dielma fastidiosa, Longicatena caecimuris, Lactococcus lactis cremoris, Tyzzerella nexilis, Hungatella effluvia, Klebsiella quasipneumoniae subsp. Similipneumoniae, Klebsiella oxytoca, and Veillonella tobetsuensis. [0146] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are a Prevotella bacteria selected from the group consisting of Prevotella albensis, Prevotella amnii, Prevotella bergensis, Prevotella bivia, Prevotella brevis, Prevotella bryantii, Prevotella buccae, Prevotella buccalis, Prevotella copri, Prevotella dentalis, Prevotella denticola, Prevotella disiens, Prevotella histicola, Prevotella intermedia, Prevotella maculosa, Prevotella marshii, Prevotella melaninogenica, Prevotella micans, Prevotella multiformis, Prevotella nigrescens, Prevotella oralis, Prevotella oris, Prevotella oulorum, Prevotella pallens, Prevotella salivae, Prevotella stercorea, Prevotella tannerae, Prevotella timonensis, Prevotella jejuni, Prevotella aurantiaca, Prevotella baroniae, Prevotella colorans, Prevotella corporis, Prevotella dentasini, Prevotella enoeca, Prevotella falsenii, Prevotella fusca, Prevotella heparinolytica, Prevotella loescheii, Prevotella multisaccharivorax, Prevotella nanceiensis, Prevotella oryzae, Prevotella paludivivens, Prevotella pleuritidis, Prevotella ruminicola, Prevotella saccharolytica, Prevotella scopos, Prevotella shahii, Prevotella zoogleoformans, and Prevotella veroralis. [0147] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are a strain of bacteria comprising a genomic sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity (e.g., at least 99.5% sequence identity, at least 99.6% sequence identity, at least 99.7% sequence identity, at least 99.8% sequence identity, at least 99.9% sequence identity) to the genomic sequence of the strain of bacteria deposited with the ATCC Deposit number as provided in Table 3. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are a strain of bacteria comprising a 16S sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity (e.g., at least 99.5% sequence identity, at least 99.6% sequence identity, at least 99.7% sequence identity, at least 99.8% sequence identity, at least 99.9% sequence identity) to the 16S sequence of the strain of bacteria deposited with the ATCC Deposit number as provided in Table 3. [0148] The Negativicutes class includes the families Veillonellaceae, Selenomonadaceae, Acidaminococcaceae, and Sporomusaceae. The Negativicutes class includes the genera Megasphaera, Selenomonas, Propionospora, and Acidaminococcus. Exemplary Negativicutes species include, but are not limited to, Megasphaera sp., Selenomonas felix, Acidaminococcus intestini, and Propionospora sp. [0149] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Negativicutes class. [0150] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Veillonellaceae family. [0151] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Selenomonadaceae family. [0152] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Acidaminococcaceae family. [0153] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Sporomusaceae family. [0154] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Megasphaera genus. [0155] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Selenomonas genus. [0156] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Propionospora genus. [0157] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Acidaminococcus genus. [0158] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Megasphaera sp. bacteria. [0159] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Selenomonas felix bacteria. [0160] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Acidaminococcus intestini bacteria. [0161] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Propionospora sp. bacteria. [0162] The Oscillospiraceae family within the Clostridia class of microorganisms are common commensal organisms of vertebrates. [0163] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Clostridia class. [0164] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Oscillospiraceae family. [0165] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Faecalibacterium genus. [0166] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Fournierella genus. [0167] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Harryflintia genus. [0168] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Agathobaculum genus. [0169] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Faecalibacterium prausnitzii (e.g., Faecalibacterium prausnitzii Strain A) bacteria. [0170] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Fournierella massiliensis (e.g., Fournierella massiliensis Strain A) bacteria. [0171] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Harryflintia acetispora (e.g., Harryflintia acetispora Strain A) bacteria. [0172] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Agathobaculum sp. (e.g., Agathobaculum sp. Strain A) bacteria. [0173] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are a strain of Agathobaculum sp. In some embodiments, the Agathobaculum sp. strain is a strain comprising at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity (e.g., at least 99.5% sequence identity, at least 99.6% sequence identity, at least 99.7% sequence identity, at least 99.8% sequence identity, at least 99.9% sequence identity) to the nucleotide sequence (e.g., genomic sequence, 16S sequence, CRISPR sequence) of the Agathobaculum sp. Strain A (ATCC Deposit Number PTA-125892). In some embodiments, the Agathobaculum sp. strain is the Agathobaculum sp. Strain A (ATCC Deposit Number PTA- 125892). [0174] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the class Bacteroidia [phylum Bacteroidota]. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are bacteria of order Bacteroidales. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the family Porphyromonadaceae. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the family Prevotellaceae. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are bacteria of the class Bacteroidia wherein the cell envelope structure of the bacteria is diderm. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are bacteria of the class Bacteroidia that stain gram-negative. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are bacteria of the class Bacteroidia wherein the bacteria are diderm and the bacteria stain gram-negative. [0175] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are bacteria of the class Clostridia [phylum Firmicutes]. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the order Eubacteriales. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the family Oscillispiraceae. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the family Lachnospiraceae. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the family Peptostreptococcaceae. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the family Clostridiales family XIII/ Incertae sedis 41. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the class Clostridia wherein the cell envelope structure of the bacteria is monoderm. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the class Clostridia that stain gram-negative. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the class Clostridia that stain gram-positive. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the class Clostridia wherein the cell envelope structure of the bacteria is monoderm and the bacteria stain gram-negative. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the class Clostridia wherein the cell envelope structure of the bacteria is monoderm and the bacteria stain gram-positive. [0176] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the class Negativicutes [phylum Firmicutes]. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the order Veillonellales. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the family Veillonelloceae. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the order Selenomonadales. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are bacteria of the family Selenomonadaceae. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the family Sporomusaceae. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the class Negativicutes wherein the cell envelope structure of the bacteria is diderm. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the class Negativicutes wherein the cell envelope structure of the bacteria is diderm and the bacteria stain gram-negative. [0177] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the class Synergistia [phylum Synergistota]. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the order Synergistales. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the family Synergistaceae. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the class Synergistia wherein the cell envelope structure of the bacteria is diderm. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the class Synergistia that stain gram-negative. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the class Synergistia wherein the cell envelope structure of the bacteria is diderm and the bacteria stain gramnegative. [0178] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are from one strain of bacteria, e.g., a strain provided herein. [0179] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are from one strain of bacteria (e.g., a strain provided herein) or from more than one strain provided herein. [0180] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Lactococcus lactis cremoris bacteria, e.g., a strain comprising at least 90% or at least 99% genomic, 16S and/or CRISPR sequence identity to the nucleotide sequence of the Lactococcus lactis cremoris Strain A (ATCC designation number PTA-125368). In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Lactococcus bacteria, e.g., Lactococcus lactis cremoris Strain A (ATCC designation number PTA-125368). [0181] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Prevotella bacteria, e.g., a strain comprising at least 90% or at least 99% genomic, 16S and/or CRISPR sequence identity to the nucleotide sequence of the Prevotella Strain B 50329 (NRRL accession number B 50329). In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Prevotella bacteria, e.g., Prevotella Strain B 50329 (NRRL accession number B 50329). [0182] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Prevotella histicola bacteria, e.g., a strain comprising at least 90% or at least 99% genomic, 16S and/or CRISPR sequence identity to the nucleotide sequence of the Prevotella histicola bacteria deposited as ATCC designation number PTA- 126140. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Prevotella histicola bacteria, e.g., Prevotella histicola bacteria deposited as ATCC designation number PTA-126140. [0183] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Bifidobacterium bacteria, e.g., a strain comprising at least 90% or at least 99% genomic, 16S and/or CRISPR sequence identity to the nucleotide sequence of the Bifidobacterium bacteria deposited as ATCC designation number PTA-125097. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Bifidobacterium bacteria, e.g., Bifidobacterium bacteria deposited as ATCC designation number PTA-125097. [0184] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Veillonella bacteria, e.g., a strain comprising at least 90% or at least 99% genomic, 16S and/or CRISPR sequence identity to the nucleotide sequence of the Veillonella bacteria deposited as ATCC designation number PTA-125691. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Veillonella bacteria, e.g., Veillonella bacteria deposited as ATCC designation number PTA-125691. [0185] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Ruminococcus gnavus bacteria. In some embodiments, the Ruminococcus gnavus bacteria are a strain comprising at least 90% (or at least 97%) genomic, 16S and/or CRISPR sequence identity to the nucleotide sequence of the Ruminococcus gnavus bacteria deposited as ATCC designation number PTA-126695. In some embodiments, the Ruminococcus gnavus bacteria are a strain comprising at least 99% genomic, 16S and/or CRISPR sequence identity to the nucleotide sequence of the Ruminococcus gnavus bacteria deposited as ATCC designation number PTA-126695. In some embodiments, the Ruminococcus gnavus bacteria are Ruminococcus gnavus bacteria deposited as ATCC designation number PTA-126695. [0186] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Megasphaera sp. bacteria. In some embodiments, the Megasphaera sp. bacteria are a strain comprising at least 90% (or at least 97%) genomic, 16S and/or CRISPR sequence identity to the nucleotide sequence of the Megasphaera sp. bacteria deposited as ATCC designation number PTA-126770. In some embodiments, the Megasphaera sp. bacteria are a strain comprising at least 99% genomic, 16S and/or CRISPR sequence identity to the nucleotide sequence of the Megasphaera sp. bacteria deposited as ATCC designation number PTA-126770. In some embodiments, the Megasphaera sp. bacteria are Megasphaera sp. bacteria deposited as ATCC designation number PTA-126770. [0187] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Fournierella massiliensis bacteria. In some embodiments, the Fournierella massiliensis bacteria are a strain comprising at least 90% (or at least 97%) genomic, 16S and/or CRISPR sequence identity to the nucleotide sequence of the Fournierella massiliensis bacteria deposited as ATCC designation number PTA-126696. In some embodiments, the Fournierella massiliensis bacteria are a strain comprising at least 99% genomic, 16S and/or CRISPR sequence identity to the nucleotide sequence of the Fournierella massiliensis bacteria deposited as ATCC designation number PTA-126696. In some embodiments, the Fournierella massiliensis bacteria are Fournierella massiliensis bacteria deposited as ATCC designation number PTA-126696. [0188] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Harryflintia acetispora bacteria. In some embodiments, the Harryflintia acetispora bacteria are a strain comprising at least 90% (or at least 97%) genomic, 16S and/or CRISPR sequence identity to the nucleotide sequence of the Harryflintia acetispora bacteria deposited as ATCC designation number PTA-126694. In some embodiments, the Harryflintia acetispora bacteria are a strain comprising at least 99% genomic, 16S and/or CRISPR sequence identity to the nucleotide sequence of the Harryflintia acetispora bacteria deposited as ATCC designation number PTA-126694. In some embodiments, the Harryflintia acetispora bacteria are Harryflintia acetispora bacteria deposited as ATCC designation number PTA-126694. [0189] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are bacteria that produce metabolites, e.g., the bacteria produce butyrate, iosine, proprionate, or tryptophan metabolites. [0190] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are bacteria that produce butyrate. In some embodiments, the bacteria are from the genus Blautia, Christensella, Copracoccus, Eubacterium, Lachnosperacea, Megasphaera, or Roseburia. [0191] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are bacteria that produce iosine. In some embodiments, the bacteria are from the genus Bifidobacterium, Lactobacillus, or Olsenella. [0192] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are bacteria that produce proprionate. In some embodiments, the bacteria are from the genus Akkermansia, Bacteriodes, Dialister, Eubacterium, Megasphaera, Parabacteriodes, Prevotella, Ruminococcus, or Veillonella. [0193] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are bacteria that produce tryptophan metabolites. In some embodiments, the bacteria are from the genus Lactobacillus or Peptostreptococcus. [0194] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are bacteria that produce inhibitors of histone deacetylase 3 (HDAC3). In some embodiments, the bacteria are from the species Bariatricus massiliensis, Faecalibacterium prausnitzii, Megasphaera massiliensis, or Roseburia intestinalis. [0195] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are from the genus Alloiococcus, Bacillus, Catenibacterium, Corynebacterium, Cupriavidus, Enhydrobacter, Exiguobacterium, Faecalibacterium, Geobacillus, Methylobacterium, Micrococcus, Morganella, Proteus, Pseudomonas, Rhizobium, or Sphingomonas. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are from the genus Cutibacterium. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are from the species Cutibacterium avidum. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are from the genus Lactobacillus. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are from the species Lactobacillus gasseri. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are from the genus Dysosmobacter. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are from the species Dysosmobacter welbionis. [0196] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the genus Alloiococcus, Bacillus, Catenibacterium, Corynebacterium, Cupriavidus, Enhydrobacter, Exiguobacterium, Faecalibacterium, Geobacillus, Methylobacterium, Micrococcus, Morganella, Proteus, Pseudomonas, Rhizobium, or Sphingomonas. [0197] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the Cutibacterium genus. In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Cutibacterium avidum bacteria. [0198] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the genus Leuconostoc. [0199] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the genus Lactobacillus. [0200] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are of the genus Akkermansia, Bacillus, Blautia, Cupriavidus, Enhydrobacter, Faecalibacterium, Lactobacillus, Lactococcus, Micrococcus, Morganella, Propionibacterium, Proteus, Rhizobium, or Streptococcus. [0201] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Leuconostoc holzapfelii bacteria. [0202] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Akkermansia muciniphila, Cupriavidus metallidurans, Faecalibacterium prausnitzii, Lactobacillus casei, Lactobacillus plantarum, Lactobacillus paracasei, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus sakei, or Streptococcus pyogenes bacteria. [0203] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Lactobacillus casei, Lactobacillus plantarum, Lactobacillus paracasei, Lactobacillus plantarum, Lactobacillus rhamnosus, or Lactobacillus sakei bacteria. [0204] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are from a genus selected from the group consisting of Acinetobacter; Deinococcus; Helicobacter; Rhodococcus; Weissella cibaria; Alloiococcus; Atopobium; Catenibacterium; Corynebacterium; Exiguobacterium; Geobacillus; Methylobacterium; Micrococcus; Morganella; Proteus; Rhizobium; Rothia; Sphingomonas; Sphingomonas; and Leuconostoc. [0205] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are from a species selected from the group consisting of Acinetobacter baumanii; Deinococcus radiodurans; Helicobacter pylori; Rhodococcus equi; Weissella cibaria; Alloiococcus otitis; Atopobium vaginae; Catenibacterium mituokai; Corynebacterium glutamicum; Exiguobacterium aurantiacum; Geobacillus stearothermophilus; Methylobacterium jeotgali; Micrococcus luteus; Morganella morganii; Proteus mirabilis; Rhizobium leguminosarum; Rothia amarae; Sphingomonas paucimobilis; and Sphingomonas koreens. [0206] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are from Leuconostoc holzapfelii bacteria. In some embodiments, the mEVs are from Leuconostoc holzapfelii Ceb-kc-003 (KCCM11830P) bacteria. [0207] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Megasphaera sp. bacteria (e.g., from the strain with accession number NCIMB 43385, NCIMB 43386 or NCIMB 43387). [0208] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Megasphaera massiliensis bacteria (e.g., from the strain with accession number NCIMB 42787, NCIMB 43388 or NCIMB 43389). [0209] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Megasphaera massiliensis bacteria (e.g., from the strain with accession number DSM 26228). [0210] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Parabacteroides distasonis bacteria (e.g., from the strain with accession number NCIMB 42382). [0211] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Megasphaera massiliensis bacteria (e.g., from the strain with accession number NCIMB 43388 or NCIMB 43389), or a derivative thereof. See, e.g., WO 2020/120714. In some embodiments, the Megasphaera massiliensis bacteria is a strain comprising at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity (e.g., at least 99.5% sequence identity, at least 99.6% sequence identity, at least 99.7% sequence identity, at least 99.8% sequence identity, at least 99.9% sequence identity) to the nucleotide sequence (e.g., genomic sequence, 16S sequence, and/or CRISPR sequence) of Megasphaera massiliensis bacteria from the strain with accession number NCIMB 43388 or NCIMB 43389. In some embodiments, the Megasphaera massiliensis bacteria is the strain with accession number NCIMB 43388 or NCIMB 43389. [0212] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Megasphaera massiliensis bacteria strain deposited under accession number NCIMB 42787, or a derivative thereof. See, e.g., WO 2018/229216. In some embodiments, the Megasphaera massiliensis bacteria is a strain comprising at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity (e.g., at least 99.5% sequence identity, at least 99.6% sequence identity, at least 99.7% sequence identity, at least 99.8% sequence identity, at least 99.9% sequence identity) to the nucleotide sequence (e.g., genomic sequence, 16S sequence, and/or CRISPR sequence) of the Megasphaera massiliensis bacteria strain deposited under accession number NCIMB 42787. In some embodiments, the Megasphaera massiliensis bacteria is the strain deposited under accession number NCIMB 42787. [0213] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Megasphaera spp. bacteria from the strain with accession number NCIMB 43385, NCIMB 43386 or NCIMB 43387, or a derivative thereof. See, e.g., WO 2020/120714. In some embodiments, the Megasphaera sp. bacteria is a strain comprising at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity (e.g., at least 99.5% sequence identity, at least 99.6% sequence identity, at least 99.7% sequence identity, at least 99.8% sequence identity, at least 99.9% sequence identity) to the nucleotide sequence (e.g., genomic sequence, 16S sequence, and/or CRISPR sequence) of the Megasphaera sp. from a strain with accession number NCIMB 43385, NCIMB 43386 or NCIMB 43387. In some embodiments, the Megasphaera sp. bacteria is the strain with accession number NCIMB 43385, NCIMB 43386 or NCIMB 43387. [0214] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Parabacteroides distasonis bacteria deposited under accession number NCIMB 42382, or a derivative thereof. See, e.g., WO 2018/229216. In some embodiments, the Parabacteroides distasonis bacteria is a strain comprising at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity (e.g., at least 99.5% sequence identity, at least 99.6% sequence identity, at least 99.7% sequence identity, at least 99.8% sequence identity, at least 99.9% sequence identity) to the nucleotide sequence (e.g., genomic sequence, 16S sequence, and/or CRISPR sequence) of the Parabacteroides distasonis bacteria deposited under accession number NCIMB 42382. In some embodiments, the Parabacteroides distasonis bacteria is the strain deposited under accession number NCIMB 42382. [0215] In some embodiments, the bacteria or the bacteria from which the mEVs are obtained and/or derived are Megasphaera massiliensis bacteria deposited under accession number DSM 26228, or a derivative thereof. See, e.g., WO 2018/229216. In some embodiments, the Megasphaera massiliensis bacteria is a strain comprising at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity (e.g., at least 99.5% sequence identity, at least 99.6% sequence identity, at least 99.7% sequence identity, at least 99.8% sequence identity, at least 99.9% sequence identity) to the nucleotide sequence (e.g., genomic sequence, 16S sequence, and/or CRISPR sequence) of Megasphaera massiliensis bacteria deposited under accession number DSM 26228. In some embodiments, the Megasphaera massiliensis bacteria is the strain deposited under accession number DSM 26228. Table 2: Bacteria by Class

Table 3: Exemplary Bacterial Strains

Table 4: Exemplary Bacterial Strains

Table 5. Exemplary Bacterial Strains

Production of Processed Microbial Extracellular Vesicles (pmEVs) [0216] In certain aspects, the pmEVs described herein can be prepared using any method known in the art. [0217] In some embodiments, the pmEVs are prepared without a pmEV purification step. For example, in some embodiments, bacteria from which the pmEVs described herein are released are killed using a method that leaves the bacterial pmEVs intact, and the resulting bacterial components, including the pmEVs, are used in the methods and compositions described herein. In some embodiments, the bacteria are killed using an antibiotic (e.g., using an antibiotic described herein). In some embodiments, the bacteria are killed using UV irradiation. [0218] In some embodiments, the pmEVs described herein are purified from one or more other bacterial components. Methods for purifying pmEVs from bacteria (and optionally, other bacterial components) are known in the art. In some embodiments, pmEVs are prepared from bacterial cultures using methods described in Thein, et al. (J. Proteome Res.9(12):6135-6147 (2010)) or Sandrini et al. (Bio-protocol 4(21): e1287 (2014)), each of which is hereby incorporated by reference in its entirety. In some embodiments, the bacteria are cultured to high optical density and then centrifuged to pellet bacteria (e.g., at 10,000- 15,000 x g for 10- 15 min at room temperature or 4°C). In some embodiments, the supernatants are discarded and cell pellets are frozen at -80ºC. In some embodiments, cell pellets are thawed on ice and resuspended in 100 mM Tris-HCl, pH 7.5 supplemented with 1 mg/mL DNase I. In some embodiments, cells are lysed using an Emulsiflex C-3 (Avestin, Inc.) under conditions recommended by the manufacturer. In some embodiments, debris and unlysed cells are pelleted by centrifugation at 10,000 x g for 15 min at 4ºC. In some embodiments, supernatants are then centrifuged at 120,000 x g for 1 hour at 4ºC. In some embodiments, pellets are resuspended in ice-cold 100 mM sodium carbonate, pH 11, incubated with agitation for 1 hour at 4ºC, and then centrifuged at 120,000 x g for 1 hour at 4ºC. In some embodiments, pellets are resuspended in 100 mM Tris-HCl, pH 7.5, re- centrifuged at 120,000 x g for 20 min at 4ºC, and then resuspended in 0.1 M Tris-HCl, pH 7.5 or in PBS. In some embodiments, samples are stored at -20ºC. [0219] In certain aspects, pmEVs are obtained and/or derived by methods adapted from Sandrini et al.2014. In some embodiments, bacterial cultures are centrifuged at 10,000-15,500 x g for 10-15 min at room temp or at 4ºC. In some embodiments, cell pellets are frozen at -80ºC and supernatants are discarded. In some embodiments, cell pellets are thawed on ice and resuspended in 10 mM Tris-HCl, pH 8.0, 1 mM EDTA supplemented with 0.1 mg/mL lysozyme. In some embodiments, samples are incubated with mixing at room temp or at 37ºC for 30 min. In some embodiments, samples are re-frozen at -80ºC and thawed again on ice. In some embodiments, DNase I is added to a final concentration of 1.6 mg/mL and MgCl₂ to a final concentration of 100 mM. In some embodiments, samples are sonicated using a QSonica Q500 sonicator with 7 cycles of 30 sec on and 30 sec off. In some embodiments, debris and unlysed cells are pelleted by centrifugation at 10,000 x g for 15 min. at 4ºC. In some embodiments, supernatants are then centrifuged at 110,000 x g for 15 min at 4ºC. In some embodiments, pellets are resuspended in 10 mM Tris-HCl, pH 8.0, 2% Triton X-100 and incubated 30-60 min with mixing at room temperature. In some embodiments, samples are centrifuged at 110,000 x g for 15 min at 4ºC. In some embodiments, pellets are resuspended in PBS and stored at -20ºC. [0220] In certain aspects, a method of forming (e.g., preparing) isolated bacterial pmEVs, described herein, comprises the steps of: (a) centrifuging a bacterial culture, thereby forming a first pellet and a first supernatant, wherein the first pellet comprises cells; (b) discarding the first supernatant;(c) resuspending the first pellet in a solution; (d) lysing the cells; (e) centrifuging the lysed cells, thereby forming a second pellet and a second supernatant; (f) discarding the second pellet and centrifuging the second supernatant, thereby forming a third pellet and a third supernatant; (g) discarding the third supernatant and resuspending the third pellet in a second solution, thereby forming the isolated bacterial pmEVs. [0221] In some embodiments, the method further comprises the steps of: (h) centrifuging the solution of step (g), thereby forming a fourth pellet and a fourth supernatant; (i) discarding the fourth supernatant and resuspending the fourth pellet in a third solution. In some embodiments, the method further comprises the steps of: (j) centrifuging the solution of step (i), thereby forming a fifth pellet and a fifth supernatant; and (k) discarding the fifth supernatant and resuspending the fifth pellet in a fourth solution. [0222] In some embodiments, the centrifugation of step (a) is at 10,000 x g. In some embodiments the centrifugation of step (a) is for 10-15 minutes. In some embodiments, the centrifugation of step (a) is at 4ºC or room temperature. In some embodiments, step (b) further comprises freezing the first pellet at -80ºC. In some embodiments, the solution in step (c) is 100 mM Tris-HCl, pH 7.5 supplemented with 1 mg/ml DNaseI. In some embodiments, the solution in step (c) is 10 mM Tris-HCl, pH 8.0, 1 mM EDTA, supplemented with 0.1 mg/ml lysozyme. In some embodiments, step (c) further comprises incubating for 30 minutes at 37ºC or room temperature. In some embodiments, step (c) further comprises freezing the first pellet at -80ºC. In some embodiments, step (c) further comprises adding DNase I to a final concentration of 1.6 mg/ml. In some embodiments, step (c) further comprises adding MgCl₂ to a final concentration of 100 mM. In some embodiments, the cells are lysed in step (d) via homogenization. In some embodiments, the cells are lysed in step (d) via emulsiflex C3. In some embodiments, the cells are lysed in step (d) via sonication. In some embodiments, the cells are sonicated in 7 cycles, wherein each cycle comprises 30 seconds of sonication and 30 seconds without sonication. In some embodiments, the centrifugation of step (e) is at 10,000 x g. In some embodiments, the centrifugation of step (e) is for 15 minutes. In some embodiments, the centrifugation of step (e) is at 4ºC or room temperature. [0223] In some embodiments, the centrifugation of step (f) is at 120,000 x g. In some embodiments, the centrifugation of step (f) is at 110,000 x g. In some embodiments, the centrifugation of step (f) is for 1 hour. In some embodiments, the centrifugation of step (f) is for 15 minutes. In some embodiments, the centrifugation of step (f) is at 4ºC or room temperature. In some embodiments, the second solution in step (g) is 100 mM sodium carbonate, pH 11. In some embodiments, the second solution in step (g) is 10 mM Tris-HCl pH 8.0, 2% triton X-100. In some embodiments, step (g) further comprises incubating the solution for 1 hour at 4ºC. In some embodiments, step (g) further comprises incubating the solution for 30-60 minutes at room temperature. In some embodiments, the centrifugation of step (h) is at 120,000 x g. In some embodiments, the centrifugation of step (h) is at 110,000 x g. In some embodiments, the centrifugation of step (h) is for 1 hour. In some embodiments, the centrifugation of step (h) is for 15 minutes. In some embodiments, the centrifugation of step (h) is at 4ºC or room temperature. In some embodiments, the third solution in step (i) is 100 mM Tris-HCl, pH 7.5. In some embodiments, the third solution in step (i) is PBS. In some embodiments, the centrifugation of step (j) is at 120,000 x g. In some embodiments, the centrifugation of step (j) is for 20 minutes. In some embodiments, the centrifugation of step (j) is at 4ºC or room temperature. In some embodiments, the fourth solution in step (k) is 100 mM Tris-HCl, pH 7.5 or PBS. [0224] pmEVs obtained and/or derived by methods provided herein may be further purified by size-based column chromatography, by affinity chromatography, and by gradient ultracentrifugation, using methods that may include, but are not limited to, use of a sucrose gradient or Optiprep gradient. Briefly, using a sucrose gradient method, if ammonium sulfate precipitation or ultracentrifugation were used to concentrate the filtered supernatants, pellets are resuspended in 60% sucrose, 30 mM Tris, pH 8.0. If filtration was used to concentrate the filtered supernatant, the concentrate is buffer exchanged into 60% sucrose, 30 mM Tris, pH 8.0, using an Amicon Ultra column. Samples are applied to a 35- 60% discontinuous sucrose gradient and centrifuged at 200,000 x g for 3-24 hours at 4°C. Briefly, using an Optiprep gradient method, if ammonium sulfate precipitation or ultracentrifugation were used to concentrate the filtered supernatants, pellets are resuspended in 35% Optiprep in PBS. In some embodiments, if filtration was used to concentrate the filtered supernatant, the concentrate is diluted using 60% Optiprep to a final concentration of 35% Optiprep. Samples are applied to a 35-60% discontinuous sucrose gradient and centrifuged at 200,000 x g for 3-24 hours at 4°C. [0225] In some embodiments, to confirm sterility and isolation of the pmEV preparations, pmEVs are serially diluted onto agar medium used for routine culture of the bacteria being tested, and incubated using routine conditions. Non-sterile preparations are passed through a 0.22 µm filter to exclude intact cells. To further increase purity, isolated pmEVs may be DNase or proteinase K treated. [0226] In some embodiments, the sterility of the pmEV preparations can be confirmed by plating a portion of the pmEVs onto agar medium used for standard culture of the bacteria used in the generation of the pmEVs and incubating using standard conditions. [0227] In some embodiments select pmEVs are isolated and enriched by chromatography and binding surface moieties on pmEVs. In other embodiments, select pmEVs are isolated and/or enriched by fluorescent cell sorting by methods using affinity reagents, chemical dyes, recombinant proteins or other methods known to one skilled in the art. [0228] The pmEVs can be analyzed, e.g., as described in Jeppesen et al. (2019) Cell 177:428. [0229] In some embodiments, pmEVs are lyophilized. [0230] In some embodiments, pmEVs are gamma irradiated (e.g., at 17.5 or 25 kGy). [0231] In some embodiments, pmEVs are UV irradiated. [0232] In some embodiments, pmEVs are heat inactivated (e.g., at 50°C for two hours or at 90°C for two hours). [0233] In some embodiments, pmEVs are acid treated. [0234] In some embodiments, pmEVs are oxygen sparged (e.g., at 0.1 vvm for two hours). [0235] The phase of growth can affect the amount or properties of bacteria. In the methods of pmEV preparation provided herein, pmEVs can be isolated, e.g., from a culture, at the start of the log phase of growth, midway through the log phase, and/or once stationary phase growth has been reached. Production of Secreted Microbial Extracellular Vesicles (smEVs) [0236] In certain aspects, the smEVs described herein can be prepared using any method known in the art. [0237] In some embodiments, the smEVs are prepared without an smEV purification step. For example, in some embodiments, bacteria described herein are killed using a method that leaves the smEVs intact and the resulting bacterial components, including the smEVs, are used in the methods and compositions described herein. In some embodiments, the bacteria are killed using an antibiotic (e.g., using an antibiotic described herein). In some embodiments, the bacteria are killed using UV irradiation. In some embodiments, the bacteria are heat-killed. [0238] In some embodiments, the smEVs described herein are purified from one or more other bacterial components. Methods for purifying smEVs from bacteria are known in the art. In some embodiments, smEVs are prepared from bacterial cultures using methods described in S. Bin Park, et al. PLoS ONE.6(3):e17629 (2011) or G. Norheim, et al. PLoS ONE.10(9): e0134353 (2015) or Jeppesen, et al. Cell 177:428 (2019), each of which is hereby incorporated by reference in its entirety. In some embodiments, the bacteria are cultured to high optical density and then centrifuged to pellet bacteria (e.g., at 10,000 x g for 30 min at 4°C, at 15,500 x g for 15 min at 4°C). In some embodiments, the culture supernatants are then passed through filters to exclude intact bacterial cells (e.g., a 0.22 µm filter). In some embodiments, the supernatants are then subjected to tangential flow filtration, during which the supernatant is concentrated, species smaller than 100 kDa are removed, and the media is partially exchanged with PBS. In some embodiments, filtered supernatants are centrifuged to pellet bacterial smEVs (e.g., at 100,000-150,000 x g for 1-3 hours at 4°C, at 200,000 x g for 1-3 hours at 4°C). In some embodiments, the smEVs are further purified by resuspending the resulting smEV pellets (e.g., in PBS), and applying the resuspended smEVs to an Optiprep (iodixanol) gradient or gradient (e.g., a 30-60% discontinuous gradient, a 0-45% discontinuous gradient), followed by centrifugation (e.g., at 200,000 x g for 4-20 hours at 4°C). smEV bands can be collected, diluted with PBS, and centrifuged to pellet the smEVs (e.g., at 150,000 x g for 3 hours at 4°C, at 200,000 x g for 1 hour at 4°C). The purified smEVs can be stored, for example, at -80°C or -20°C until use. In some embodiments, the smEVs are further purified by treatment with DNase and/or proteinase K. [0239] For example, in some embodiments, cultures of bacteria can be centrifuged at 11,000 x g for 20-40 min at 4°C to pellet bacteria. Culture supernatants may be passed through a 0.22 µm filter to exclude intact bacterial cells. Filtered supernatants may then be concentrated using methods that may include, but are not limited to, ammonium sulfate precipitation, ultracentrifugation, or filtration. For example, for ammonium sulfate precipitation, 1.5-3 M ammonium sulfate can be added to filtered supernatant slowly, while stirring at 4ºC. Precipitations can be incubated at 4ºC for 8-48 hours and then centrifuged at 11,000 x g for 20-40 min at 4ºC. The resulting pellets contain bacteria smEVs and other debris. Using ultracentrifugation, filtered supernatants can be centrifuged at 100,000- 200,000 x g for 1-16 hours at 4°C. The pellet of this centrifugation contains bacteria smEVs and other debris such as large protein complexes. In some embodiments, using a filtration technique, such as through the use of an Amicon Ultra spin filter or by tangential flow filtration, supernatants can be filtered so as to retain species of molecular weight > 50 or 100 kDa. [0240] Alternatively, smEVs can be obtained and/or derived from bacteria cultures continuously during growth, or at selected time points during growth, for example, by connecting a bioreactor to an alternating tangential flow (ATF) system (e.g., XCell ATF from Repligen). The ATF system retains intact cells (> 0.22 µm) in the bioreactor, and allows smaller components (e.g., smEVs, free proteins) to pass through a filter for collection. For example, the system may be configured so that the < 0.22 µm filtrate is then passed through a second filter of 100 kDa, allowing species such as smEVs between 0.22 µm and 100 kDa to be collected, and species smaller than 100 kDa to be pumped back into the bioreactor. Alternatively, the system may be configured to allow for medium in the bioreactor to be replenished and/or modified during growth of the culture. smEVs collected by this method may be further purified and/or concentrated by ultracentrifugation or filtration as described above for filtered supernatants. [0241] smEVs obtained and/or derived by methods provided herein may be further purified by size-based column chromatography, by affinity chromatography, by ion- exchange chromatography, and by gradient ultracentrifugation, using methods that may include, but are not limited to, use of a sucrose gradient or Optiprep gradient. Briefly, using a sucrose gradient method, if ammonium sulfate precipitation or ultracentrifugation were used to concentrate the filtered supernatants, pellets are resuspended in 60% sucrose, 30 mM Tris, pH 8.0. If filtration was used to concentrate the filtered supernatant, the concentrate is buffer exchanged into 60% sucrose, 30 mM Tris, pH 8.0, using an Amicon Ultra column. Samples are applied to a 35-60% discontinuous sucrose gradient and centrifuged at 200,000 x g for 3-24 hours at 4°C. Briefly, using an Optiprep gradient method, if ammonium sulfate precipitation or ultracentrifugation were used to concentrate the filtered supernatants, pellets are resuspended in PBS and 3 volumes of 60% Optiprep are added to the sample. In some embodiments, if filtration was used to concentrate the filtered supernatant, the concentrate is diluted using 60% Optiprep to a final concentration of 35% Optiprep. Samples are applied to a 0-45% discontinuous Optiprep gradient and centrifuged at 200,000 x g for 3-24 hours at 4°C, e.g., 4-24 hours at 4°C. [0242] In some embodiments, to confirm sterility and isolation of the smEV preparations, smEVs are serially diluted onto agar medium used for routine culture of the bacteria being tested, and incubated using routine conditions. Non-sterile preparations are passed through a 0.22 µm filter to exclude intact cells. To further increase purity, isolated smEVs may be DNase or proteinase K treated. [0243] In some embodiments, for preparation of smEVs used for in vivo injections, purified smEVs are processed as described previously (G. Norheim, et al. PLoS ONE. 10(9): e0134353 (2015)). Briefly, after sucrose gradient centrifugation, bands containing smEVs are resuspended to a final concentration of 50 µg/mL in a solution containing 3% sucrose or other solution suitable for in vivo injection known to one skilled in the art. This solution may also contain adjuvant, for example aluminum hydroxide at a concentration of 0-0.5% (w/v). In some embodiments, for preparation of smEVs used for in vivo injections, smEVs in PBS are sterile-filtered to < 0.22 µm. [0244] In certain embodiments, to make samples compatible with further testing (e.g., to remove sucrose prior to TEM imaging or in vitro assays), samples are buffer exchanged into PBS or 30 mM Tris, pH 8.0 using filtration (e.g., Amicon Ultra columns), dialysis, or ultracentrifugation (200,000 x g, ≥ 3 hours, 4ºC) and resuspension. [0245] In some embodiments, the sterility of the smEV preparations can be confirmed by plating a portion of the smEVs onto agar medium used for standard culture of the bacteria used in the generation of the smEVs and incubating using standard conditions. [0246] In some embodiments, select smEVs are isolated and enriched by chromatography and binding surface moieties on smEVs. In other embodiments, select smEVs are isolated and/or enriched by fluorescent cell sorting by methods using affinity reagents, chemical dyes, recombinant proteins or other methods known to one skilled in the art. [0247] The smEVs can be analyzed, e.g., as described in Jeppesen, et al. Cell 177:428 (2019). [0248] In some embodiments, smEVs are lyophilized. [0249] In some embodiments, smEVs are gamma irradiated (e.g., at 17.5 or 25 kGy). [0250] In some embodiments, smEVs are UV irradiated. [0251] In some embodiments, smEVs are heat inactivated (e.g., at 50°C for two hours or at 90°C for two hours). [0252] In some embodiments, smEVs s are acid treated. [0253] In some embodiments, smEVs are oxygen sparged (e.g., at 0.1 vvm for two hours). [0254] The phase of growth can affect the amount or properties of bacteria and/or smEVs produced by bacteria. For example, in the methods of smEV preparation provided herein, smEVs can be isolated, e.g., from a culture, at the start of the log phase of growth, midway through the log phase, and/or once stationary phase growth has been reached. [0255] The growth environment (e.g., culture conditions) can affect the amount of smEVs produced by bacteria. For example, the yield of smEVs can be increased by an smEV inducer, as provided in Table 6. Table 6: Culture Techniques to Increase smEV Production

[0256] In the methods of smEVs preparation provided herein, the method can optionally include exposing a culture of bacteria to an smEV inducer prior to isolating smEVs from the bacterial culture. The culture of bacteria can be exposed to an smEV inducer at the start of the log phase of growth, midway through the log phase, and/or once stationary phase growth has been reached. Methods of Detecting and/or Quantifying Bacteria and mEVs [0257] In certain aspects, provided herein is method of detecting (e.g., identifying) and/or quantifying the genus, species and/or strain of bacteria from which microbial extracellular vesicle (mEVs) in a sample are obtained and/or derived. In some embodiments, the method comprises: (a) contacting the sample comprising the mEVs with an antibody or antigen binding fragment thereof that specifically binds to an antigen on the mEVs; and (b) detecting the binding of the antibody or antigen binding fragment thereof to the mEVs, thereby detecting (e.g., identifying) and/or quantifying the genus, species and/or strain of bacteria from which the mEVs are obtained and/or derived (e.g., using ELISA, flow cytometry, SPR, Western blot, or microscopy). In certain embodiments, the antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof that specifically binds to an antigen on a certain type of bacterial mEVs. In certain embodiments, the antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof provided herein. In some embodiments, the antibody or antigen binding fragment thereof specifically binds to an antigen on an mEVs obtained and/or derived from bacteria of the genus Prevotella (e.g., bacteria of the species Prevotella histicola, such as bacteria of the strain Prevotella Strain B 50329). In some embodiments provided herein, the antibody or antigen binding fragment thereof specifically binds to an antigen on an mEVs obtained and/or derived from bacteria of the genus Fournierella (e.g., bacteria of the species Fournierella massiliensis, such as bacteria of the strain Fournierella massiliensis Strain A (ATCC Deposit Number PTA-126696)). In some embodiments provided herein, the antibody or antigen binding fragment thereof specifically binds to an antigen on mEVs from bacteria of the genus Veillonella (e.g., bacteria of the species Veillonella parvula, such as bacteria of the strain Veillonella parvula Strain A (ATCC Accession Number PTA-125691)). [0258] In certain aspects, provided herein is method of detecting (e.g., identifying) and/or quantifying the genus, species and/or strain of bacteria in a sample. In some embodiments, the method comprises: (a) contacting the sample comprising the bacteria with an antibody that specifically binds to an antigen on the bacteria; and (b) detecting the binding of the antibody to the bacteria, thereby detecting (e.g., identifying) and/or quantifying the genus, species and/or strain of bacteria (e.g., using ELISA, flow cytometry; or microscopy). In certain embodiments, the antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof that specifically binds to an antigen on a certain type of bacteria. In certain embodiments, the antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof provided herein. In some embodiments, the antibody or antigen binding fragment thereof specifically binds to an antigen on bacteria of the genus Prevotella (e.g., bacteria of the species Prevotella histicola, such as bacteria of the strain Prevotella Strain B 50329). In some embodiments provided herein, the antibody or antigen binding fragment thereof specifically binds to an antigen on bacteria of the genus Fournierella (e.g., bacteria of the species Fournierella massiliensis, such as bacteria of the strain Fournierella massiliensis Strain A (ATCC Deposit Number PTA-126696)). In some embodiments provided herein, the antibody or antigen binding fragment thereof specifically binds to an antigen on bacteria of the genus Veillonella (e.g., bacteria of the species Veillonella parvula, such as bacteria of the strain Veillonella parvula Strain A (ATCC Accession Number PTA-125691)). [0259] In certain aspects, provided herein is a method of detecting (e.g., identifying) and/or quantifying the genus, species and/or strain of bacteria from which microbial extracellular vesicle (mEVs) in a sample are obtained and/or derived, the method comprising: (a) contacting the sample comprising the mEVs with a first antibody or antigen binding fragment thereof that specifically binds to an antigen on the mEVs; (b) contacting the sample comprising the mEVs with a second antibody or antigen binding fragment thereof that specifically binds to an antigen on the mEVs; and (c) detecting the binding of the first and/or the second antibody or antigen binding fragments thereof to the mEVs (e.g., using ELISA, flow cytometry; or microscopy), thereby detecting (e.g., identifying) and/or quantifying the genus, species and/or strain of bacteria from which the mEVs are obtained and/or derived. In certain embodiments, the first and/or second antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof that binds to a certain type of bacterial mEVs. In certain embodiments, the first and/or second antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof provided herein. In some embodiments, the first and/or second antibody or antigen binding fragment thereof binds mEVs obtained and/or derived from bacteria of the genus Prevotella (e.g., bacteria of the species Prevotella histicola, such as bacteria of the strain Prevotella Strain B 50329). In some embodiments provided herein, the first and/or second antibody or antigen binding fragment thereof binds mEVs obtained and/or derived from bacteria of the genus Fournierella (e.g., bacteria of the species Fournierella massiliensis, such as bacteria of the strain Fournierella massiliensis Strain A (ATCC Deposit Number PTA-126696)). In some embodiments provided herein, the antibody or antigen binding fragment thereof specifically binds to an antigen on bacteria of the genus Veillonella (e.g., bacteria of the species Veillonella parvula, such as bacteria of the strain Veillonella parvula Strain A (ATCC Accession Number PTA-125691)). [0260] In certain aspects, provided herein is a method of detecting (e.g., identifying) and or quantifying the genus, species and/or strain of bacteria in a sample, the method comprising: (a) contacting the sample comprising the bacteria with a first antibody or antigen binding fragment thereof that specifically binds to an antigen on the bacteria; (b) contacting the sample comprising the bacteria with a second antibody or antigen binding fragment thereof that specifically binds to an antigen on the bacteria; and (c) detecting the binding of the first and/or the second antibody or antigen binding fragments thereof to the bacteria (e.g., using ELISA, flow cytometry; or microscopy), thereby detecting (e.g., identifying) and or quantifying the genus, species and/or strain of bacteria. In certain embodiments, the first and/or second antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof that binds to a certain type of bacteria. In certain embodiments, the first and/or second antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof provided herein. In some embodiments, the first and/or second antibody or antigen binding fragment thereof binds bacteria of the genus Prevotella (e.g., bacteria of the species Prevotella histicola, such as bacteria of the strain Prevotella Strain B 50329). In some embodiments provided herein, the first and/or second antibody or antigen binding fragment thereof binds bacteria of the genus Fournierella (e.g., bacteria of the species Fournierella massiliensis, such as bacteria of the strain Fournierella massiliensis Strain A (ATCC Deposit Number PTA-126696)). In some embodiments provided herein, the antibody or antigen binding fragment thereof specifically binds to an antigen on bacteria of the genus Veillonella (e.g., bacteria of the species Veillonella parvula, such as bacteria of the strain Veillonella parvula Strain A (ATCC Accession Number PTA-125691)). [0261] In certain embodiments, the first antibody and/or the second antibody is detectably labeled. [0262] In certain embodiments, the methods provided herein include use of a biochip array. In some embodiments, mEVs are captured on the biochip array (e.g., using an antibody provided herein) and then subjected to analysis (e.g., using a different antibody provided herein). In some embodiments, mEVs are captured with capture reagents (e.g., antibodies provided herein) immobilized to a solid support, such as a biochip, a multi-well microtiter plate, a resin, or a nitrocellulose membrane that is subsequently probed (e.g., with a second antibody provided herein, such as a biotinylated antibody). Capture can be on a chromatographic surface or a biospecific surface. For example, a sample containing the mEVs, is contacted an antibody-coated surface of a biochip for a sufficient time to allow binding of the antibodies to the mEVs. Unbound mEVs are washed from the surface using a suitable eluent, such as phosphate buffered saline. The bound mEVs are then probed with a second antibody provided herein (e.g., a biotinylated or detectably labeled second antibody). Binding of the second antibody to the captured mEVs is then detected. In some embodiments, the second antibody comprises a detectable label, such as a fluorescent moiety or a chemical conjugate that detectably reacts to a reagent in certain conditions. [0263] In some embodiments of the methods provided herein, the sample is from a drug substance, a drug product, a microbial (e.g., bacterial) culture, or an in-process sample from a manufacturing or purification process. In some embodiments of the methods provided herein, the sample is from a subject (e.g., human) such as a subject to whom a composition has been administered. For example, the sample can be from blood, serum, saliva, urine, feces, bile, cerebral spinal fluid, semen, or vaginal fluid, from the subject. In some embodiments of the methods provided herein, the sample is from a subject’s blood. [0264] In some embodiments of methods provided herein, the sample is, or includes mEVs obtained and/or derived from a microbe that is an archaea, fungi, microscopic algae, protozoan, or parasite. In some embodiments, methods provided herein are useful to detect mEVs in a sample, quantify mEVs in a sample, and/or identify the genus, species, or strain of a microbe from which mEVs in a sample are obtained and/or derived, where the mEVs are obtained and/or derived from a microbe that is an archaea, fungi, microscopic algae, protozoan, or parasite. [0265] In some embodiments of methods provided herein, the sample is, or includes mEVs obtained and/or derived from a mammalian cell. In some embodiments, methods provided herein are useful to detect mEVs in a sample, quantify mEVs in a sample, and/or identify the genus, species, or strain of a cell from which mEVs in a sample are obtained and/or derived, where the mEVs are obtained and/or derived from a mammalian cell. Methods of Purifying Bacteria and mEVs [0266] In certain aspects, provided herein is a method purifying bacteria or mEVs (e.g., a type of bacteria or mEVs) from a solution (e.g., a fermentation solution). The method comprising: (a) contacting the solution comprising the bacteria or mEVs with an antibody or antigen binding fragment thereof that specifically binds to an antigen on the bacteria or mEVs; and (b) eluting the bacteria or mEVs from the antibody, thereby purifying the bacteria or mEVs from the solution. [0267] In certain embodiments, the antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof that specifically binds to an antigen on a certain type of bacteria or mEVs. In certain embodiments, the antibody or antigen binding fragment thereof is an antibody or antigen binding fragment thereof provided herein. In some embodiments, the antibody or antigen binding fragment thereof specifically binds to an antigen on bacteria or mEVs obtained and/or derived from bacteria of the genus Prevotella (e.g., bacteria of the species Prevotella histicola, such as bacteria of the strain Prevotella Strain B 50329). In some embodiments provided herein, the antibody or antigen binding fragment thereof specifically binds to an antigen on bacteria or mEVs obtained and/or derived from bacteria of the genus Fournierella (e.g., bacteria of the species Fournierella massiliensis, such as bacteria of the strain Fournierella massiliensis Strain A (ATCC Deposit Number PTA-126696)). In some embodiments provided herein, the antibody or antigen binding fragment thereof binds to mEVs obtained and/or derived from bacteria of the genus Veillonella (e.g., bacteria of the species Veillonella parvula, such as bacteria of the strain Veillonella parvula Strain A (ATCC Accession Number PTA- 125691)). [0268] In certain embodiments of the compositions and methods provided herein, the antibody or antigen binding fragment thereof is detectably labeled. In some embodiments, the antibody or antigen binding fragment thereof is immobilized on a solid support. In some embodiments, the solid support may be any one of, but are not limited to, the following: biochips, microwells, beads, columns, flow cells, and membranes. In some embodiments, the solid support is a bead. In some embodiments, the bead is a latex bead. In some embodiments, the bead is a magnetic bead. In some embodiments, the bead is an agarose bead. In some embodiments, the solid support is a column. In some embodiments, the column is any one of, but are not limited to, the following: protein A, protein G column, streptavidin column, spin-column, and resin columns. [0269] In some embodiments, the present disclosure provides a method of purifying mEVs obtained and/or derived from a microbe that is an archaea, fungi, microscopic algae, protozoan, or parasite. In some embodiments, methods provided herein are useful to purify mEVs from a sample, where the mEVs are obtained and/or derived from a microbe that is an archaea, fungi, microscopic algae, protozoan, or parasite. [0270] In some embodiments, the present disclosure provides a method of purifying mEVs obtained and/or derived from a mammalian cell. In some embodiments, methods provided herein are useful to purify mEVs from a sample, where the mEVs are obtained and/or derived from a mammalian cell. Methods of Quantifying mEVs [0271] Methods of quantifying mEVs are also provided herein. In one aspect, a quantitative ELISA methodology is used to detect and quantify the amount of mEVs obtained and/or derived from a particular microbial source are present in a sample. Similar to the indirect sandwich ELISA, a first or primary antibody that specifically binds to a first epitope of an antigen present in the mEVs is used to capture mEVs. A secondary or labeling antibody that specifically binds to a second epitope of the antigen or that specifically binds to a second antigen associated with mEVs from a particular microbial source is used to label the bound mEV. The second antibody may have a conjugate that can be quantifiably detected or otherwise used in quantifying the amount of mEVs in a sample. For example, in some embodiments, the secondary antibody is biotinylated. Biotin moieties can be bound by streptavidin, which can be conjugated to a detectable label. For example, streptavidin is often conjugated to a horse-radish peroxidase (HRP) that generates a detectable and quantifiable signal in the presence of certain reagents (e.g., TMB (3, 3', 5, 5'- tetramethylbenzidine). [0272] In another aspect provided herein, a quantitative SPR methodology is used to detect and quantify the amount of mEVs obtained and/or derived from a particular microbial source present in a sample. SPR analysis monitors interactions between a ligand immobilized on the surface of a sensor chip and an analyte in solution passing over the sensor chip. The analysis allows real-time, label-free monitoring of binding phenomena and affinity between the ligand or antibody and the analyte. In some embodiments, the analyte in solution is mEVs. In some embodiments the ligand or antibody is an antibody or an antigen-binding fragment thereof that specifically binds to the mEVs. For example, the antibody or an antigen-binding fragment thereof may specifically bind to an antigen/epitope on the surface of the mEVs. [0273] In some embodiments, the surface of the sensor chip comprises streptavidin, which will bind and capture a biotinylated antibody or an antigen-binding fragment thereof that specifically binds to mEVs antigen or epitope. In some embodiments, the antibody is a polyclonal antibody or an antigen-binding fragment thereof. In some embodiments, the antibody is a monoclonal antibody or an antigen-binding fragment thereof. In some embodiments, concentration-dependent binding allows for quantification of mEVs present in a sample. [0274] In some embodiments, the present disclosure provides a method of quantifying mEVs obtained and/or derived from a microbe that is an archaea, fungi, microscopic algae, protozoan, or parasite. In some embodiments, methods provided herein are useful to quantify mEVs from a sample, where the mEVs are obtained and/or derived from a microbe that is an archaea, fungi, microscopic algae, protozoan, or parasite. [0275] In some embodiments, the present disclosure provides a method of quantifying mEVs obtained and/or derived from a mammalian cell. In some embodiments, methods provided herein are useful to quantify mEVs from a sample, where the mEVs are obtained and/or derived from a mammalian cell. EXAMPLARY EMBODIMENTS [0276] The present disclosure provides, among other things, the following enumerated embodiments: 1. A method of identifying the genus of bacteria from which a microbial extracellular vesicle (mEV) in a sample is obtained and/or derived, the method comprising: (a) contacting the sample comprising the mEV with an antibody that specifically binds to an antigen on the mEV; and (b) detecting the binding of the antibody to the mEV, thereby identifying the genus of bacteria from which the mEV is obtained and/or derived. 2. A method of identifying the species of bacteria from which a microbial extracellular vesicle (mEV) in a sample is obtained and/or derived, the method comprising: (a) contacting the sample comprising the mEV with an antibody that specifically binds to an antigen on the mEV; and (b) detecting the binding of the antibody to the mEV, thereby identifying the species of bacteria from which the mEV is obtained and/or derived. 3. A method of identifying the strain of bacteria from which a microbial extracellular vesicle (mEV) in a sample is obtained and/or derived, the method comprising: (a) contacting the sample comprising the mEV with an antibody that specifically binds to an antigen on the mEV; and (b) detecting the binding of the antibody to the mEV, thereby identifying the strain of bacteria from which the mEV is obtained and/or derived. 4. The method of any one of embodiments 1-3, wherein the antibody is detectably labeled. 5. The method of any one of embodiments 1-4, wherein the binding is detected in step (b) using ELISA, flow cytometry, or microscopy. 6. The method of any one of embodiments 1-5, wherein the antibody comprises a heavy chain CDR3 of SEQ ID NO: 5. 7. The method of embodiment 6, wherein the antibody comprises a heavy chain CDR1 of SEQ ID NO: 3 and a heavy chain CDR2 of SEQ ID NO: 4. 8. The method of embodiment 6 or embodiment 7, wherein the antibody comprises a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 2. 9. The method of embodiment 8, wherein the antibody comprises a heavy chain variable region of SEQ ID NO: 2. 10. The method of any one of embodiments 6-9, wherein the antibody comprises a heavy chain having a sequence at least 95% identical to SEQ ID NO: 1. 11. The method of embodiment 10, wherein the antibody comprises a heavy chain of SEQ ID NO: 1. 12. The method of any one of embodiments 6-11, wherein the antibody comprises a light chain CDR3 of SEQ ID NO: 10. 13. The method of embodiment 12, wherein the antibody comprises a light chain CDR1 of SEQ ID NO: 8 and a light chain CDR2 of SEQ ID NO: 9. 14. The method of any one of embodiments 6-13, wherein the antibody comprises a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 7. 15. The method of embodiment 14, wherein the antibody comprises a light chain variable region of SEQ ID NO: 7. 16. The method of any one of embodiments 6-15, wherein the antibody comprises a light chain having a sequence at least 95% identical to SEQ ID NO: 6. 17. The method of embodiment 16, wherein the antibody comprises a light chain of SEQ ID NO: 6. 18. The method of any one of embodiments 1-5, wherein the antibody comprises a heavy chain CDR3 of SEQ ID NO: 15. 19. The method of embodiment 18, wherein the antibody comprises a heavy chain CDR1 of SEQ ID NO: 13 and a heavy chain CDR2 of SEQ ID NO: 14. 20. The method of embodiment 18 or embodiment 19, wherein the antibody comprises a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 12. 21. The method of embodiment 20, wherein the antibody comprises a heavy chain variable region of SEQ ID NO: 12. 22. The method of any one of embodiments 18-21, wherein the antibody comprises a heavy chain having a sequence at least 95% identical to SEQ ID NO: 11. 23. The method of embodiment 22, wherein the antibody comprises a heavy chain of SEQ ID NO: 11. 24. The method of any one of embodiments 18-23, wherein the antibody comprises a light chain CDR3 of SEQ ID NO: 20. 25. The method of embodiment 24, wherein the antibody comprises a light chain CDR1 of SEQ ID NO: 18 and a light chain CDR2 of SEQ ID NO: 19. 26. The method of any one of embodiments 18-25, wherein the antibody comprises a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 17. 27. The method of embodiment 26, wherein the antibody comprises a light chain variable region of SEQ ID NO: 17. 28. The method of any one of embodiments 18-27, wherein the antibody comprises a light chain having a sequence at least 95% identical to SEQ ID NO: 16. 29. The method of embodiment 28, wherein the antibody comprises a light chain of SEQ ID NO: 16. 30. The method of any one of embodiments 5-29, wherein the mEV is conjugated to a latex bead prior to step (a). 31. The method of embodiment 30, wherein the latex bead is a super active latex bead. 32. The method of embodiment 31, wherein the super active latex bead is an aldehyde/sulfate bead. 33. A method of identifying the genus of bacteria from which a microbial extracellular vesicle (mEV) in a sample is obtained and/or derived, the method comprising: (a) contacting the sample comprising the mEV with a first antibody that specifically binds to an antigen on the mEV; (b) contacting the sample comprising the mEV with a second antibody that specifically binds to an antigen on the mEV; (c) detecting the binding of the first and/or the second antibody to the mEV, thereby identifying the genus of bacteria from which the mEV is obtained and/or derived. 34. A method of identifying the species of bacteria from which a microbial extracellular vesicle (mEV) in a sample is obtained and/or derived, the method comprising: (a) contacting the sample comprising the mEV with a first antibody that specifically binds to an antigen on the mEV; (b) contacting the sample comprising the mEV with a second antibody that specifically binds to an antigen on the mEV; (c) detecting the binding of the first and/or the second antibody to the mEV, thereby identifying the species of bacteria from which the mEV is obtained and/or derived. 35. A method of identifying the strain of bacteria from which a microbial extracellular vesicle (mEV) in a sample is obtained and/or derived, the method comprising: (a) contacting the sample comprising the mEV with a first antibody that specifically binds to an antigen on the mEV; (b) contacting the sample comprising the mEV with a second antibody that specifically binds to an antigen on the mEV; (c) detecting the binding of the first and/or the second antibody to the mEV, thereby identifying the strain of bacteria from which the mEV is obtained and/or derived. 36. The method of any one of embodiments 33-35, wherein the first antibody and/or the second antibody is detectably labeled. 37. The method of any one of embodiments 33-35, wherein the binding is detected in step (c) using ELISA, flow cytometry, or microscopy. 38. The method of any one of embodiments 33-35, wherein first antibody is tethered to a surface. 39. The method of embodiment 38, wherein the surface is a biochip, microwell, bead, column, or a membrane. 40. The method of embodiment 38 or 39, wherein the mEV is captured on the surface by the antibody. 41. The method of embodiment 40, wherein the second antibody binds to the captured mEV. 42. The method of embodiment 41, wherein the second antibody is detectably labeled and step (c) comprises detecting the detectable label. 43. The method of embodiment 41, wherein step (c) further comprises contacting the second antibody with a detectably labeled third antibody specific for the second antibody and further comprises detecting the detectable label. 44. The method of embodiment 41, wherein the second antibody is biotin labeled and step (c) further comprises contacting the second antibody with a streptavidin-labeled detectable label and further comprises detecting the detectable label. 45. The method of any one of embodiments 33-44, wherein the first antibody comprises a heavy chain CDR3 of SEQ ID NO: 5. 46. The method of embodiment 45, wherein the first antibody comprises a heavy chain CDR1 of SEQ ID NO: 3 and a heavy chain CDR2 of SEQ ID NO: 4. 47. The method of embodiment 45 or embodiment 46, wherein the first antibody comprises a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 2. 48. The method of embodiment 47, wherein the first antibody comprises a heavy chain variable region of SEQ ID NO: 2. 49. The method of any one of embodiments 45-48, wherein the first antibody comprises a heavy chain having a sequence at least 95% identical to SEQ ID NO: 1. 50. The method of embodiment 49, wherein the first antibody comprises a heavy chain of SEQ ID NO: 1. 51. The method of any one of embodiments 45-50, wherein the first antibody comprises a light chain CDR3 of SEQ ID NO: 10. 52. The method of embodiment 51, wherein the first antibody comprises a light chain CDR1 of SEQ ID NO: 8 and a light chain CDR2 of SEQ ID NO: 9. 53. The method of any one of embodiments 45-52, wherein the first antibody comprises a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 7. 54. The method of embodiment 53, wherein the first antibody comprises a light chain variable region of SEQ ID NO: 7. 55. The method of any one of embodiments 45-54, wherein the first antibody comprises a light chain having a sequence at least 95% identical to SEQ ID NO: 6. 56. The method of embodiment 55, wherein the first antibody comprises a light chain of SEQ ID NO: 6. 57. The method of any one of embodiments 45-56, wherein the second antibody comprises a heavy chain CDR3 of SEQ ID NO: 15. 58. The method of embodiment 57, wherein the second antibody comprises a heavy chain CDR1 of SEQ ID NO: 13 and a heavy chain CDR2 of SEQ ID NO: 14. 59. The method of embodiment 57 or embodiment 58, wherein the second antibody comprises a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 12. 60. The method of embodiment 59, wherein the second antibody comprises a heavy chain variable region of SEQ ID NO: 12. 61. The method of any one of embodiments 57-60, wherein the second antibody comprises a heavy chain having a sequence at least 95% identical to SEQ ID NO: 11. 62. The method of embodiment 61, wherein the second antibody comprises a heavy chain of SEQ ID NO: 11. 63. The method of any one of embodiments 57-62, wherein the second antibody comprises a light chain CDR3 of SEQ ID NO: 20. 64. The method of embodiment 63, wherein the second antibody comprises a light chain CDR1 of SEQ ID NO: 18 and a light chain CDR2 of SEQ ID NO: 19. 65. The method of any one of embodiments 57-64, wherein the second antibody comprises a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 17. 66. The method of embodiment 65, wherein the second antibody comprises a light chain variable region of SEQ ID NO: 17. 67. The method of any one of embodiments 57-66, wherein the second antibody comprises a light chain having a sequence at least 95% identical to SEQ ID NO: 16. 68. The method of embodiment 67, wherein the second antibody comprises a light chain of SEQ ID NO: 16. 69. The method of any one of embodiments 33-44, wherein the first antibody comprises a heavy chain CDR3 of SEQ ID NO: 15. 70. The method of embodiment 69, wherein the first antibody comprises a heavy chain CDR1 of SEQ ID NO: 13 and a heavy chain CDR2 of SEQ ID NO: 14. 71. The method of embodiment 69 or embodiment 70, wherein the first antibody comprises a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 12. 72. The method of embodiment 71, wherein the first antibody comprises a heavy chain variable region of SEQ ID NO: 12. 73. The method of any one of embodiments 69-72, wherein the first antibody comprises a heavy chain having a sequence at least 95% identical to SEQ ID NO: 11. 74. The method of embodiment 73, wherein the first antibody comprises a heavy chain of SEQ ID NO: 11. 75. The method of any one of embodiments 69-74, wherein the first antibody comprises a light chain CDR3 of SEQ ID NO: 20. 76. The method of embodiment 75, wherein the first antibody comprises a light chain CDR1 of SEQ ID NO: 18 and a light chain CDR2 of SEQ ID NO: 19. 77. The method of any one of embodiments 69-76, wherein the first antibody comprises a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 17. 78. The method of embodiment 77, wherein the first antibody comprises a light chain variable region of SEQ ID NO: 17. 79. The method of any one of embodiments 69-78, wherein the first antibody comprises a light chain having a sequence at least 95% identical to SEQ ID NO: 16. 80. The method of embodiment 79, wherein the first antibody comprises a light chain of SEQ ID NO: 16. 81. The method of any one of embodiments 69-80, wherein the second antibody comprises a heavy chain CDR3 of SEQ ID NO: 5. 82. The method of embodiment 81, wherein the second antibody comprises a heavy chain CDR1 of SEQ ID NO: 3 and a heavy chain CDR2 of SEQ ID NO: 4. 83. The method of embodiment 81 or embodiment 82, wherein the second antibody comprises a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 2. 84. The method of embodiment 83, wherein the second antibody comprises a heavy chain variable region of SEQ ID NO: 2. 85. The method of any one of embodiments 81-84, wherein the second antibody comprises a heavy chain having a sequence at least 95% identical to SEQ ID NO: 1. 86. The method of embodiment 85, wherein the second antibody comprises a heavy chain of SEQ ID NO: 1. 87. The method of any one of embodiments 81-86, wherein the second antibody comprises a light chain CDR3 of SEQ ID NO: 10. 88. The method of embodiment 87, wherein the second antibody comprises a light chain CDR1 of SEQ ID NO: 8 and a light chain CDR2 of SEQ ID NO: 9. 89. The method of any one of embodiments 81-88, wherein the second antibody comprises a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 7. 90. The method of embodiment 89, wherein the second antibody comprises a light chain variable region of SEQ ID NO: 7. 91. The method of any one of embodiments 81-90, wherein the second antibody comprises a light chain having a sequence at least 95% identical to SEQ ID NO: 6. 92. The method of embodiment 91, wherein the second antibody comprises a light chain of SEQ ID NO: 6. 93. The method of any one of embodiments 33-92, wherein the first antibody is contacted to the sample before the second antibody. 94. The method of any one of embodiments 33-92, wherein the second antibody is contacted to the sample before the first antibody. 95. The method of any one of embodiments 33-92, wherein the first and second antibody are contacted to the sample simultaneously. 96. The method of any one of embodiments 37-95, wherein the mEV is conjugated to a latex bead prior to step (a). 97. The method of embodiment 96, wherein the latex bead is a super active latex bead. 98. The method of embodiment 97, wherein the super active latex bead is an aldehyde/sulfate bead. 99. The method of any one of embodiments 1-99, wherein the mEV is a secreted mEV (smEV). 100. The method of any one of embodiments 1-99, wherein the mEV is a processed mEV (pmEV). 101. The method of any one of embodiments 1-100, wherein the bacteria are of the genus Prevotella. 102. The method of any one of embodiments 1-101, wherein the bacteria are of the species Prevotella histicola. 103. The method of any one of embodiments 1-102, wherein the bacteria are of the strain Prevotella Strain B 50329. 104. The method of any one of embodiments 1-100, wherein the bacteria are of the genus Fournierella. 105. The method of any one of embodiments 1-100, wherein the bacteria are of the species Fournierella massiliensis. 106. The method of any one of embodiments 1-100, wherein the bacteria are of the strain is Fournierella massiliensis Strain A (ATCC Deposit Number PTA-126696). 107. A method of identifying the genus of bacteria in a sample, the method comprising: (a) contacting the sample comprising the bacteria with an antibody that specifically binds to an antigen on the bacteria; and (b) detecting the binding of the antibody to the bacteria, thereby identifying the genus of bacteria. 108. A method of identifying the species of bacteria in a sample, the method comprising: (a) contacting the sample comprising the bacteria with an antibody that specifically binds to an antigen on the bacteria; and (b) detecting the binding of the antibody to the bacteria, thereby identifying the species of bacteria. 109. A method of identifying the strain of bacteria in a sample, the method comprising: (a) contacting the sample comprising the bacteria with an antibody that specifically binds to an antigen on the bacteria; and (b) detecting the binding of the antibody to the bacteria thereby identifying the strain of bacteria. 110. The method of any one of embodiments 107-109, wherein the antibody is detectably labeled. 111. The method of any one of embodiments 107-110, wherein the binding is detected in step (b) using ELISA, flow cytometry, or microscopy. 112. The method of any one of embodiments 107-111, wherein the antibody comprises a heavy chain CDR3 of SEQ ID NO: 5. 113. The method of embodiment 112, wherein the antibody comprises a heavy chain CDR1 of SEQ ID NO: 3 and a heavy chain CDR2 of SEQ ID NO: 4. 114. The method of embodiment 112 or embodiment 113, wherein the antibody comprises a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 2. 115. The method of embodiment 114, wherein the antibody comprises a heavy chain variable region of SEQ ID NO: 2. 116. The method of any one of embodiments 112-115, wherein the antibody comprises a heavy chain having a sequence at least 95% identical to SEQ ID NO: 1. 117. The method of embodiment 116, wherein the antibody comprises a heavy chain of SEQ ID NO: 1. 118. The method of any one of embodiments 112-117, wherein the antibody comprises a light chain CDR3 of SEQ ID NO: 10. 119. The method of embodiment 118, wherein the antibody comprises a light chain CDR1 of SEQ ID NO: 8 and a light chain CDR2 of SEQ ID NO: 9. 120. The method of any one of embodiments 112-119, wherein the antibody comprises a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 7. 121. The method of embodiment 120, wherein the antibody comprises a light chain variable region of SEQ ID NO: 7. 122. The method of any one of embodiments 112-121, wherein the antibody comprises a light chain having a sequence at least 95% identical to SEQ ID NO: 6. 123. The method of embodiment 122, wherein the antibody comprises a light chain of SEQ ID NO: 6. 124. The method of any one of embodiments 107-111, wherein the antibody comprises a heavy chain CDR3 of SEQ ID NO: 15. 125. The method of embodiment 124, wherein the antibody comprises a heavy chain CDR1 of SEQ ID NO: 13 and a heavy chain CDR2 of SEQ ID NO: 14. 126. The method of embodiment 124 or embodiment 125, wherein the antibody comprises a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 12. 127. The method of embodiment 126, wherein the antibody comprises a heavy chain variable region of SEQ ID NO: 12. 128. The method of any one of embodiments 124-127, wherein the antibody comprises a heavy chain having a sequence at least 95% identical to SEQ ID NO: 11. 129. The method of embodiment 128, wherein the antibody comprises a heavy chain of SEQ ID NO: 11. 130. The method of any one of embodiments 124-129, wherein the antibody comprises a light chain CDR3 of SEQ ID NO: 20. 131. The method of embodiment 130, wherein the antibody comprises a light chain CDR1 of SEQ ID NO: 18 and a light chain CDR2 of SEQ ID NO: 19. 132. The method of any one of embodiments 124-131, wherein the antibody comprises a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 17. 133. The method of embodiment 132, wherein the antibody comprises a light chain variable region of SEQ ID NO: 17. 134. The method of any one of embodiments 124-133, wherein the antibody comprises a light chain having a sequence at least 95% identical to SEQ ID NO: 16. 135. The method of embodiment 134, wherein the antibody comprises a light chain of SEQ ID NO: 16. 136. A method of identifying the genus of bacteria in a sample, the method comprising: (a) contacting the sample comprising the bacteria with a first antibody that specifically binds to an antigen on the bacteria; (b) contacting the sample comprising the bacteria with a second antibody that specifically binds to an antigen on the bacteria; (c) detecting the binding of the first and/or the second antibody to the bacteria, thereby identifying the genus of bacteria. 137. A method of identifying the species of bacteria in a sample, the method comprising: (a) contacting the sample comprising the bacteria with a first antibody that specifically binds to an antigen on the bacteria; (b) contacting the sample comprising the bacteria with a second antibody that specifically binds to an antigen on the bacteria; (c) detecting the binding of the first and/or the second antibody to the bacteria, thereby identifying the species of bacteria 138. A method of identifying the strain of bacteria in a sample, the method comprising: (a) contacting the sample comprising the bacteria with a first antibody that specifically binds to an antigen on the bacteria; (b) contacting the sample comprising the bacteria with a second antibody that specifically binds to an antigen on the bacteria; (c) detecting the binding of the first and/or the second antibody to the bacteria, thereby identifying the strain of bacteria. 139. The method of any one of embodiments 136-138, wherein the first antibody and/or the second antibody is detectably labeled. 140. The method of any one of embodiments 136-139, wherein the binding is detected in step (c) using ELISA, flow cytometry, or microscopy. 141. The method of any one of embodiments 136-139, wherein first antibody is tethered to a surface. 142. The method of embodiment 141, wherein the surface is a biochip, microwell, bead, column, or a membrane. 143. The method of embodiment 141 or 142, wherein the bacteria is captured on the surface by the antibody. 144. The method of embodiment 143, wherein, wherein the second antibody binds to the captured bacteria. 145. The method of embodiment 144, wherein the second antibody is detectably labeled and step (c) comprises detecting the detectable label. 146. The method of embodiment 144, wherein step (c) further comprises contacting the second antibody with a detectably labeled third antibody specific for the second antibody and further comprises detecting the detectable label. 147. The method of embodiment 144, wherein the second antibody is biotin labeled and step (c) further comprises contacting the second antibody with a streptavidin-labeled detectable label and further comprises detecting the detectable label. 148. The method of any one of embodiments 136-147, wherein the first antibody comprises a heavy chain CDR3 of SEQ ID NO: 5. 149. The method of embodiment 148, wherein the first antibody comprises a heavy chain CDR1 of SEQ ID NO: 3 and a heavy chain CDR2 of SEQ ID NO: 4. 150. The method of embodiment 148 or embodiment 149, wherein the first antibody comprises a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 2. 151. The method of embodiment 150, wherein the first antibody comprises a heavy chain variable region of SEQ ID NO: 2. 152. The method of any one of embodiments 148-151, wherein the first antibody comprises a heavy chain having a sequence at least 95% identical to SEQ ID NO: 1. 153. The method of embodiment 152, wherein the first antibody comprises a heavy chain of SEQ ID NO: 1. 154. The method of any one of embodiments 148-153, wherein the first antibody comprises a light chain CDR3 of SEQ ID NO: 10. 155. The method of embodiment 154, wherein the first antibody comprises a light chain CDR1 of SEQ ID NO: 8 and a light chain CDR2 of SEQ ID NO: 9. 156. The method of any one of embodiments 148-155, wherein the first antibody comprises a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 7. 157. The method of embodiment 156, wherein the first antibody comprises a light chain variable region of SEQ ID NO: 7. 158. The method of any one of embodiments 148-157, wherein the first antibody comprises a light chain having a sequence at least 95% identical to SEQ ID NO: 6. 159. The method of embodiment 158, wherein the first antibody comprises a light chain of SEQ ID NO: 6. 160. The method of any one of embodiments 148-159, wherein the second antibody comprises a heavy chain CDR3 of SEQ ID NO: 15. 161. The method of embodiment 160, wherein the second antibody comprises a heavy chain CDR1 of SEQ ID NO: 13 and a heavy chain CDR2 of SEQ ID NO: 14. 162. The method of embodiment 160 or embodiment 161, wherein the second antibody comprises a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 12. 163. The method of embodiment 162, wherein the second antibody comprises a heavy chain variable region of SEQ ID NO: 12. 164. The method of any one of embodiments 160-163, wherein the second antibody comprises a heavy chain having a sequence at least 95% identical to SEQ ID NO: 11. 165. The method of embodiment 164, wherein the second antibody comprises a heavy chain of SEQ ID NO: 11. 166. The method of any one of embodiments 160-165, wherein the second antibody comprises a light chain CDR3 of SEQ ID NO: 20. 167. The method of embodiment 166, wherein the second antibody comprises a light chain CDR1 of SEQ ID NO: 18 and a light chain CDR2 of SEQ ID NO: 19. 168. The method of any one of embodiments 160-167, wherein the second antibody comprises a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 17. 169. The method of embodiment 168, wherein the second antibody comprises a light chain variable region of SEQ ID NO: 17. 170. The method of any one of embodiments 160-166, wherein the second antibody comprises a light chain having a sequence at least 95% identical to SEQ ID NO: 16. 171. The method of embodiment 170, wherein the second antibody comprises a light chain of SEQ ID NO: 16. 172. The method of any one of embodiments 136-147, wherein the first antibody comprises a heavy chain CDR3 of SEQ ID NO: 15. 173. The method of embodiment 172, wherein the first antibody comprises a heavy chain CDR1 of SEQ ID NO: 13 and a heavy chain CDR2 of SEQ ID NO: 14. 174. The method of embodiment 172 or embodiment 173, wherein the first antibody comprises a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 12. 175. The method of embodiment 174, wherein the first antibody comprises a heavy chain variable region of SEQ ID NO: 12. 176. The method of any one of embodiments 174-175, wherein the first antibody comprises a heavy chain having a sequence at least 95% identical to SEQ ID NO: 11. 177. The method of embodiment 176, wherein the first antibody comprises a heavy chain of SEQ ID NO: 11. 178. The method of any one of embodiments 172-177, wherein the first antibody comprises a light chain CDR3 of SEQ ID NO: 20. 179. The method of embodiment 178, wherein the first antibody comprises a light chain CDR1 of SEQ ID NO: 18 and a light chain CDR2 of SEQ ID NO: 19. 180. The method of any one of embodiments 172-179, wherein the first antibody comprises a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 17. 181. The method of embodiment 180, wherein the first antibody comprises a light chain variable region of SEQ ID NO: 17. 182. The method of any one of embodiments 172-181, wherein the first antibody comprises a light chain having a sequence at least 95% identical to SEQ ID NO: 16. 183. The method of embodiment 182, wherein the first antibody comprises a light chain of SEQ ID NO: 16. 184. The method of any one of embodiments 172-183, wherein the second antibody comprises a heavy chain CDR3 of SEQ ID NO: 5. 185. The method of embodiment 184, wherein the second antibody comprises a heavy chain CDR1 of SEQ ID NO: 3 and a heavy chain CDR2 of SEQ ID NO: 4. 186. The method of embodiment 184 or embodiment 185, wherein the second antibody comprises a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 2. 187. The method of embodiment 186, wherein the second antibody comprises a heavy chain variable region of SEQ ID NO: 2. 188. The method of any one of embodiments 184-187, wherein the second antibody comprises a heavy chain having a sequence at least 95% identical to SEQ ID NO: 1. 189. The method of embodiment 188, wherein the second antibody comprises a heavy chain of SEQ ID NO: 1. 190. The method of any one of embodiments 184-189, wherein the second antibody comprises a light chain CDR3 of SEQ ID NO: 10. 191. The method of embodiment 190, wherein the second antibody comprises a light chain CDR1 of SEQ ID NO: 8 and a light chain CDR2 of SEQ ID NO: 9. 192. The method of any one of embodiments 184-191, wherein the second antibody comprises a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 7. 193. The method of embodiment 192, wherein the second antibody comprises a light chain variable region of SEQ ID NO: 7. 194. The method of any one of embodiments 184-193, wherein the second antibody comprises a light chain having a sequence at least 95% identical to SEQ ID NO: 6. 195. The method of embodiment 194, wherein the second antibody comprises a light chain of SEQ ID NO: 6. 196. The method of any one of embodiments 136-195, wherein the first antibody is contacted to the sample before the second antibody. 197. The method of any one of embodiments 136-195, wherein the second antibody is contacted to the sample before the first antibody. 198. The method of any one of embodiments 136-195, wherein the first and second antibody are contacted to the sample simultaneously. 199. The method of any one of embodiments 107-198, wherein the bacteria are of the genus Prevotella. 200. The method of any one of embodiments 107-199, wherein the bacteria are of the species Prevotella histicola. 201. The method of any one of embodiments 107-201, wherein the bacteria are of the strain Prevotella Strain B 50329. 202. The method of any one of embodiments 107-198, wherein the bacteria are of the genus Fournierella. 203. The method of any one of embodiments 107-198, wherein the bacteria are of the species Fournierella massiliensis. 204. The method of any one of embodiments 107-198, wherein the bacteria are of the strain is Fournierella massiliensis Strain A (ATCC Deposit Number PTA-126696). 205. An antibody comprising a heavy chain CDR3 of SEQ ID NO: 5. 206. The antibody of embodiment 205, wherein the antibody comprises a heavy chain CDR1 of SEQ ID NO: 3 and a heavy chain CDR2 of SEQ ID NO: 4. 207. The antibody of embodiment 205 or embodiment 206, wherein the antibody comprises a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 2. 208. The antibody of embodiment 207, wherein the antibody comprises a heavy chain variable region of SEQ ID NO: 2. 209. The antibody of any one of embodiments 205-208, wherein the antibody comprises a heavy chain having a sequence at least 95% identical to SEQ ID NO: 1. 210. The antibody of embodiment 209, wherein the antibody comprises a heavy chain of SEQ ID NO: 1. 211. The antibody of any one of embodiments 205-210, wherein the antibody comprises a light chain CDR3 of SEQ ID NO: 10. 212. The antibody of embodiment 211, wherein the antibody comprises a light chain CDR1 of SEQ ID NO: 8 and a light chain CDR2 of SEQ ID NO: 9. 213. The antibody of any one of embodiments 205-212, wherein the antibody comprises a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 7. 214. The antibody of embodiment 213, wherein the antibody comprises a light chain variable region of SEQ ID NO: 7. 215. The antibody of any one of embodiments 205-214, wherein the antibody comprises a light chain having a sequence at least 95% identical to SEQ ID NO: 6. 216. The antibody of embodiment 215, wherein the antibody comprises a light chain of SEQ ID NO: 6. 217. An antibody comprising a heavy chain CDR3 of SEQ ID NO: 15. 218. The antibody of embodiment 217, wherein the antibody comprises a heavy chain CDR1 of SEQ ID NO: 13 and a heavy chain CDR2 of SEQ ID NO: 14. 219. The antibody of embodiment 217 or embodiment 218, wherein the antibody comprises a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 12. 220. The antibody of embodiment 219, wherein the antibody comprises a heavy chain variable region of SEQ ID NO: 12. 221. The antibody of any one of embodiments 218-220, wherein the antibody comprises a heavy chain having a sequence at least 95% identical to SEQ ID NO: 11. 222. The antibody of embodiment 221, wherein the antibody comprises a heavy chain of SEQ ID NO: 11. 223. The antibody of any one of embodiments 217-222, wherein the antibody comprises a light chain CDR3 of SEQ ID NO: 20. 224. The antibody of embodiment 223, wherein the antibody comprises a light chain CDR1 of SEQ ID NO: 18 and a light chain CDR2 of SEQ ID NO: 19. 225. The antibody of any one of embodiments 217-224, wherein the antibody comprises a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 17. 226. The antibody of embodiment 225, wherein the antibody comprises a light chain variable region of SEQ ID NO: 17. 227. The antibody of any one of embodiments 217-226, wherein the antibody comprises a light chain having a sequence at least 95% identical to SEQ ID NO: 16. 228. The antibody of embodiment 227, wherein the antibody comprises a light chain of SEQ ID NO: 16. 229. The antibody of any one of embodiments 205-228, wherein the antibody binds to mEVs obtained and/or derived from bacteria of the genus Prevotella. 230. The antibody of any one of embodiments 205-229, wherein the antibody binds to mEVs obtained and/or derived from bacteria of the species Prevotella histicola. 231. The antibody of any one of embodiments 205-230, wherein the antibody binds to mEVs obtained and/or derived from bacteria of the strain Prevotella Strain B 50329. 232. The antibody of any one of embodiments 205-228, wherein the antibody binds to mEVs obtained and/or derived from bacteria of the genus Fournierella. 233. The antibody of any one of embodiments 205-228, wherein the antibody binds to mEVs obtained and/or derived from bacteria of the species Fournierella massiliensis. 234. The antibody of any one of embodiments 205-228, wherein the antibody binds to mEVs obtained and/or derived from bacteria of strain Fournierella massiliensis Strain A (ATCC Deposit Number PTA-126696). 235. A nucleic acid molecule comprising a sequence encoding a heavy chain of an antibody of any one of embodiments 205-234. 236. A nucleic acid molecule comprising a sequence encoding a light chain of an antibody of any one of embodiments 205-234. 237. A vector comprising the nucleic acid of embodiment 235 and/or embodiment 236. 238. A host cell comprising the nucleic acid of embodiment 235 or embodiment 236 or the vector of embodiment 237. 239. A method of quantifying or detecting the presence of a bacterial mEV in a sample, the method comprising: (a) contacting the sample with a first antibody that specifically binds to an antigen on the mEV; (b) contacting the sample with a second antibody that specifically binds to an antigen on the mEV; and (c) detecting the binding of the first and/or the second antibody to the mEV, thereby quantifying or detecting the presence of the mEV in the sample. 240. The method of embodiment 233, wherein the first and/or the second antibody is detectably labeled. 241. The method of any one of embodiments 233-234, wherein the binding is detected in step (b) using ELISA, flow cytometry, or microscopy. 242. The method of any of one of embodiments 233-234, wherein the first antibody is tethered to a surface. 243. The method of embodiment 236, wherein the surface is a biochip, microwell, bead, column, or a membrane. 244. The method of embodiments 236 or 237, wherein the mEV is captured on the surface by the antibody. 245. The method of embodiment 238, wherein the second antibody binds to the captured mEV. 246. The method of embodiment 239, wherein the second antibody is detectably labeled and step (c) comprises detecting the detectable label. 247. The method of embodiment 239, wherein step (c) further comprises contacting the second antibody with a detectably labeled third antibody specific for the second antibody and further comprises detecting the detectable label. 248. The method of embodiment 239, wherein the second antibody is biotin labeled and step (c) further comprises contacting the second antibody with a streptavidin-labeled detectable label and further comprises detecting the detectable label. 249. The method of any of embodiments 233-242, wherein the first antibody comprises a heavy chain CDR3 of SEQ ID NO: 15. 250. The method of embodiments 243, wherein the first antibody comprises a heavy chain CDR1 or SEQ ID NO: 13 and a heavy chain CDR2 of SEQ ID NO: 14. 251. The method of embodiment 243 or 244, wherein the first antibody comprises a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 12. 252. The method of embodiment 245, wherein the first antibody comprises a heavy chain variable region of SEQ ID NO: 12. 253. The method of any of embodiments 243-246, wherein the first antibody comprises a heavy chain having a sequence at least 95% identical to SEQ ID NO: 11. 254. The method of embodiment 247, wherein the first antibody comprises a heavy chain of SEQ ID NO: 11. 255. The method of any one of embodiments 243-248, wherein the first antibody comprises a light chain CDR3 of SEQ ID NO: 20. 256. The method of embodiment 249, wherein the first antibody comprises a light chain CDR1 of SEQ ID NO: 18 and a light CDR2 of SEQ ID NO: 19. 257. The method of any one of embodiments 243-250, wherein the first antibody comprises a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 17. 258. The method of embodiment 251, wherein the first antibody comprises a light chain variable region of SEQ ID NO: 17. 259. The method of any one of embodiments 243-252, wherein the first antibody comprises a light chain having a sequence at least 95% identical to SEQ ID NO: 16. 260. The method of embodiment 253, wherein the first antibody comprises a light chain of SEQ ID NO: 16. 261. The method of any one of embodiments 233-242, wherein the second antibody comprises a heavy chain CDR3 of SEQ ID NO: 5. 262. The method of embodiment 255, wherein the second antibody comprises a heavy chain CDR1 of SEQ ID NO: 3 and a heavy chain CDR2 of SEQ ID NO: 4. 263. The method of embodiment 255 or embodiment 256, wherein the second antibody comprises a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 2. 264. The method of embodiment 257, wherein the second antibody comprises a heavy chain variable region of SEQ ID NO: 2. 265. The method of any one of embodiments 255-258, wherein the second antibody comprises a heavy chain having a sequence at least 95% identical to SEQ ID NO: 1. 266. The method of embodiment 259, wherein the second antibody comprises a heavy chain of SEQ ID NO: 1. 267. The method of any one of embodiments 255-260, wherein the second antibody comprises a light chain CDR3 of SEQ ID NO: 10. 268. The method of embodiment 261, wherein the second antibody comprises a light chain CDR1 of SEQ ID NO: 8 and a light chain CDR2 of SEQ ID NO: 9. 269. The method of any one of embodiments 255-262, wherein the second antibody comprises a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 7. 270. The method of embodiment 263, wherein the second antibody comprises a light chain variable region of SEQ ID NO: 7. 271. The method of any one of embodiments 255-264, wherein the second antibody comprises a light chain having a sequence at least 95% identical to SEQ ID NO: 6. 272. The method of embodiment 265, wherein the second antibody comprises a light chain of SEQ ID NO: 6. 273. The method of any one of embodiments 233-266, wherein the first antibody is contacted to the sample before the second antibody. 274. The method of any one of embodiments 233-266, wherein the second antibody is contacted to the sample before the first antibody. 275. The method of any one of embodiments 233-266, wherein the first and/or the second antibody are contacted to the sample simultaneously. 276. A method of any one of embodiments 239-275, wherein the mEV in the sample is conjugated to a latex bead prior to step (a). 277. The method of embodiment 276, wherein the latex bead is a super active latex bead. 278. The method of embodiment 277, wherein the super active latex bead is an aldehyde/sulfate bead. 279. A method of quantifying or detecting the presence of a bacterial mEV in a sample, the method comprising: (a) contacting the sample comprising the mEV with an antibody that specifically binds to an antigen on the mEV; and (b) detecting the binding of the antibody to the mEV, thereby identifying the genus of bacteria from which the mEV is obtained and/or derived. 280. The method of embodiment 279, wherein the antibody is detectably labeled. 281. The method of embodiment 280, wherein the binding is detected in step (b) using ELISA, flow cytometry, or microscopy. 282. The method of embodiment 280 or 281, wherein the antibody comprises a heavy chain CDR3 of SEQ ID NO: 5. 283. The method of embodiment 282, wherein the antibody comprises a heavy chain CDR1 of SEQ ID NO: 3 and a heavy chain CDR2 of SEQ ID NO: 4. 284. The method of embodiment 282 or 283, wherein the antibody comprises a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 2. 285. The method of embodiment 284, wherein the antibody comprises a heavy chain variable region of SEQ ID NO: 2. 286. The method of any one of embodiments 282-285, wherein the antibody comprises a heavy chain having a sequence at least 95% identical to SEQ ID NO: 1. 287. The method of embodiment 286, wherein the antibody comprises a heavy chain of SEQ ID NO: 1. 288. The method of any one of embodiments 282-287, wherein the antibody comprises a light chain CDR3 of SEQ ID NO: 10. 289. The method of embodiment 288, wherein the antibody comprises a light chain CDR1 of SEQ ID NO: 8 and a light chain CDR2 of SEQ ID NO: 9. 290. The method of any one of embodiments 282-289, wherein the antibody comprises a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 7. 291. The method of embodiment 290, wherein the antibody comprises a light chain variable region of SEQ ID NO: 7. 292. The method of any one of embodiments 282-291, wherein the antibody comprises a light chain having a sequence at least 95% identical to SEQ ID NO: 6. 293. The method of embodiment 292, wherein the antibody comprises a light chain of SEQ ID NO: 6. 294. The method of embodiment 280 or 281, wherein the antibody comprises a heavy chain CDR3 of SEQ ID NO: 15. 295. The method of embodiment 294, wherein the antibody comprises a heavy chain CDR1 of SEQ ID NO: 13 and a heavy chain CDR2 of SEQ ID NO: 14. 296. The method of embodiment 294 or embodiment 295, wherein the antibody comprises a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 12. 297. The method of embodiment 296, wherein the antibody comprises a heavy chain variable region of SEQ ID NO: 12. 298. The method of any one of embodiments 294-297, wherein the antibody comprises a heavy chain having a sequence at least 95% identical to SEQ ID NO: 11. 299. The method of embodiment 298, wherein the antibody comprises a heavy chain of SEQ ID NO: 11. 300. The method of any one of embodiments 294-299, wherein the antibody comprises a light chain CDR3 of SEQ ID NO: 20. 301. The method of embodiment 299, wherein the antibody comprises a light chain CDR1 of SEQ ID NO: 18 and a light chain CDR2 of SEQ ID NO: 19. 302. The method of any one of embodiments 294-301, wherein the antibody comprises a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 17. 303. The method of embodiment 302, wherein the antibody comprises a light chain variable region of SEQ ID NO: 17. 304. The method of any one of embodiments 294-303, wherein the antibody comprises a light chain having a sequence at least 95% identical to SEQ ID NO: 16. 305. The method of embodiment 304, wherein the antibody comprises a light chain of SEQ ID NO: 16. 306. The method of any one of embodiments 239-305, wherein the mEV is an mEV obtained and/or derived from bacteria of the genus Prevotella histicola. 307. The method of any one of embodiments 239-306, wherein the mEV is an mEV obtained and/or derived from bacteria of the species Prevotella histicola. 308. The method of any one of embodiments 239-307, wherein the mEV is an mEV obtained and/or derived from bacteria strain Prevotella Strain B 50329. 309. The method of any one of embodiments 239-305, wherein the mEV is an mEV obtained and/or derived from bacteria of the genus Fournierella. 310. The method of any one of embodiments 239-305, wherein the mEV is an mEV obtained and/or derived from bacteria of the species Fournierella massiliensis. 311. The method of any one of embodiments 239-305, wherein the mEV is an mEV obtained and/or derived from bacteria of strain Fournierella massiliensis Strain A (ATCC Deposit Number PTA-126696). 312. The method of any one of embodiments 239-311, wherein the mEV is conjugated to a latex bead prior to step (a). 313. The method of embodiment 312, wherein the latex bead is a super active latex bead. 314. The method of embodiment 313, wherein the super active latex bead is an aldehyde/sulfate bead. 315. A method of purifying bacteria or microbial extracellular vesicle (mEVs) from a solution, the method comprising: (a) contacting the solution comprising the bacteria or mEVs with an antibody or antigen binding fragment thereof that specifically binds to an antigen on the bacteria or mEVs; and (b) eluting the bacteria or mEVs from the antibody or antigen binding fragment thereof, thereby purifying the bacteria or mEVs from the solution. 316. The method of embodiment 315, wherein the antibody is detectably labeled. 317. The method of any one of embodiments 315-316, wherein the antibody is tethered to a surface. 318. The method of embodiment 317, wherein the surface is a biochip, microwell, bead, column, or a membrane. 319. The method of embodiment 318, wherein the bacteria or mEVs are captured on the surface by the antibody. 320. The method of any one of embodiments 315-319, wherein the antibody comprises a heavy chain CDR3 of SEQ ID NO: 5. 321. The method of embodiment 320, wherein the antibody comprises a heavy chain CDR1 of SEQ ID NO: 3 and a heavy chain CDR2 of SEQ ID NO: 4. 322. The method of embodiment 320 or embodiment 321, wherein the antibody comprises a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 2. 323. The method of embodiment 322, wherein the antibody comprises a heavy chain variable region of SEQ ID NO: 2. 324. The method of any one of embodiments 320-323, wherein the antibody comprises a heavy chain having a sequence at least 95% identical to SEQ ID NO: 1. 325. The method of embodiment 324, wherein the antibody comprises a heavy chain of SEQ ID NO: 1. 326. The method of any one of embodiments 320-325, wherein the antibody comprises a light chain CDR3 of SEQ ID NO: 10. 327. The method of embodiment 326, wherein the antibody comprises a light chain CDR1 of SEQ ID NO: 8 and a light chain CDR2 of SEQ ID NO: 9. 328. The method of any one of embodiments 320-327, wherein the antibody comprises a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 7. 329. The method of embodiment 328, wherein the antibody comprises a light chain variable region of SEQ ID NO: 7. 330. The method of any one of embodiments 320-329, wherein the antibody comprises a light chain having a sequence at least 95% identical to SEQ ID NO: 6. 331. The method of embodiment 330, wherein the antibody comprises a light chain of SEQ ID NO: 6. 332. The method of any one of embodiments 315-319, wherein the antibody comprises a heavy chain CDR3 of SEQ ID NO: 15. 333. The method of embodiment 332, wherein the antibody comprises a heavy chain CDR1 of SEQ ID NO: 13 and a heavy chain CDR2 of SEQ ID NO: 14. 334. The method of embodiment 332 or embodiment 333, wherein the antibody comprises a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 12. 335. The method of embodiment 334, wherein the antibody comprises a heavy chain variable region of SEQ ID NO: 12. 336. The method of any one of embodiments 332-335, wherein the antibody comprises a heavy chain having a sequence at least 95% identical to SEQ ID NO: 11. 337. The method of embodiment 336, wherein the antibody comprises a heavy chain of SEQ ID NO: 11. 338. The method of any one of embodiments 332-337, wherein the antibody comprises a light chain CDR3 of SEQ ID NO: 20. 339. The method of embodiment 338, wherein the antibody comprises a light chain CDR1 of SEQ ID NO: 18 and a light chain CDR2 of SEQ ID NO: 19. 340. The method of any one of embodiments 332-339, wherein the antibody comprises a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 17. 341. The method of embodiment 340, wherein the antibody comprises a light chain variable region of SEQ ID NO: 17. 342. The method of any one of embodiments 332-341, wherein the antibody comprises a light chain having a sequence at least 95% identical to SEQ ID NO: 16. 343. The method of embodiment 342, wherein the antibody comprises a light chain of SEQ ID NO: 16. EXAMPLES Example 1: Materials and Methods Generation of polyclonal antibodies [0277] Four rabbits (New Zealand white) were immunized periodically with a batch of P. histicola 1 mEVs (gradient purified mEVs) in Complete Freund’s Adjuvant (CFA) using standard procedures. Serum was collected at each immunization (Day 0, Day 35, Day 56/58). Serum was also collected on Day 90. To enrich the specificity of the serum, the serum from Day 90 (Terminal serum) was used to generate purified IgG, using Protein A purification method. Polyclonal antibodies to F. massiliensis 1 mEVs were also generated in New Zealand white rabbits. Generation of monoclonal antibodies for ELISA [0278] Monoclonal antibodies were generated against mEVs of P. histicola 1. Balbc mice were immunized with gradient purified P. histicola 1 mEVs using an optimized Rapid Immunization Protocol (RIMMS). Splenocytes were harvested from mice that showed high polyclonal antibody serum titers. Splenic B cells were fused with myeloma cells and grown in a selection medium (ultralow bovine immunoglobin FBS containing media). The supernatant collected from the fused cells was tested for specificity to P. histicola 1 mEVs and other closely related strain and genus mEVs to choose mixed clones (multipure) specific to P. histicola 1 mEVs for further subcloning. Dilution cloning of the mixed clones generated two clones (17B01-02G10 clone and 02F09-02B04 clone) which were expanded for mAb isolation and purification. F. massiliensis 1 mEVs monoclonal antibodies were also prepared as described above. Veillonella parvula Strain A (ATCC Accession Number PTA-125691) mEVs monoclonal antibodies were prepared using a similar method by Maine Biotechnology Services (BBI Solutions –1037R Forest Avenue, Portland, Maine 04103 https://www.bbisolutions.com/en/category/antibody-development1). Antibody Characterization [0279] In-solution endoproteinase digestions of the monoclonal antibody (mAb) were performed for mAb sequencing analysis. The antibody was reduced with DTT and alkylated using iodoacetamide. The sample was equally divided into 6 aliquots for 6 individual enzyme digestions: LysC, Asp N, chymotrypsin, elastase, trypsin, and pepsin following manufacturer’s instructions. After reversed phase cleanup of each digest, samples were kept frozen until mass spectrometry analysis as described below. Mass Spectrometry [0280] Intact mass analysis with DTT reduction and PNGase F deglycosylation followed by LC-MS analysis were performed on a Thermo Scientific Orbitrap Fusion Lumos Tribrid mass spectrometer, equipped with a heated electrospray ionization source in positive ion mode with a Thermo Fisher Ultimate 3000 RSLCnano HPLC System. The sample was loaded onto a Thermo Fisher MABPAC RP analytical 4 μM, 3.0 X 50 mm column, held at 70°C. The protein was eluted at a rate of 500 μL/min using a nonlinear gradient of 10-70% acetonitrile in 0.1% formic acid. MS spectra were acquired by using full scans at 15000 resolution in the orbitrap using high mass range scanning 850- 4000 m/z. Maximum injection time was limited to 100 ms with an automatic gain control (AGC) target of 100000. Ten micro scans were employed and the RF lens was set to 45%.15V of in source CID was applied. LC-MS/MS Analysis [0281] The digests were analyzed on an Orbitrap analyzer (Orbitrap Fusion Lumos, Thermo Fisher Scientific). Both full MS scans and MS2 scans were acquired in the high resolution Orbitrap mass analyzer. MS2 data were acquired using HCD and ETD followed by HCD (EThcD) fragmentation methods. All raw data files were used for data analysis using the PEAKS AB 2.0 software. Ile/Leu Differentiation [0282] To differentiate between the isobaric amino acids, isoleucine, and leucine in the heavy and light chains of the antibodies, EThcD data, PEAKS AB I/L differentiation algorithm, and manual inspections were performed (Tables 7A and 7B).

Table 7A: Ile/Leu differentiation for the assembled sequence of Antibody 02F09- 02B04

Confidence levels are determined by conservation data (in conserved regions),

enzyme cleavage specificity and EtHCD data. Conservation data is based on the percentage of isoleucine/leucine at a specific position. If conservation data is lacking or it is a CDR residue, it has been labelled as N/A.

Table 7B: Ile/Leu differentiation for the assembled sequence of Antibody 17B01- 02G10

Indirect ELISA protocol A. P. histicola 1 [0283] mEVs of P. histicola 1, P. histicola 2, and P. melanogenica were immobilized on a Nunc Maxisorp plate at 2 µg/mL protein concentration and incubated at room temperature for 2 hours. [0284] The plate was washed 5X with PBST, blocked with 1% Casein and incubated for 1 hour at 37ºC. [0285] The plate was washed 5X with PBST, supernatant was added at 0.5ug/mL and incubated for 1hour at 37ºC. [0286] The plate was washed 5X with PBST, 1:10,000 of goat anti-mouse IgG was added and incubated for 1hour at 37ºC. [0287] The plate was washed 5X with PBST, and 3,3’,5,5’-tetramethylbenzidine (TMB) substrate was added to the plate and incubated for 20 minutes in dark at room temperature. [0288] The reaction was stopped using 1 N Hydrochloric acid and read at OD450nm and OD652nm in a spectrophotometer. B. F. massiliensis 1 [0289] mEVs of F. massiliensis 1, F. massiliensis 2, Megasphaera sp., and H. acetispora were immobilized on a Nunc Maxisorp plate at 2 µg/mL protein concentration and incubated at room temperature for 2 hours. [0290] The plate was washed 5X with PBST, blocked with 1% Casein and incubated for 1 hour at 37ºC. [0291] The plate was washed 5X with PBST, supernatant is added at 0.5 µg/mL and incubated for 1 hour at 37ºC. [0292] The plate was washed 5X with PBST, and 1:10,000 of goat anti-mouse IgG was added and incubated for 1 hour at 37ºC. [0293] The plate was washed 5X with PBST, and TMB substrate was added to the plate and incubated for 20 minutes in the dark at room temperature. [0294] The reaction was stopped using 1N Hydrochloric acid and read at OD450nm and OD_652nm in a spectrophotometer. Sandwich ELISA Procedure A. P. histicola 1 [0295] A sandwich ELISA method was developed and optimized using 17B01- 02G10 as a capture antibody and a biotinylated 02F09-02B04 clone as the secondary detection antibody. [0296] The capture antibody (17B01-02G10 clone) at 0.5 µg/mL concentration was immobilized on a Nunc maxisorp ELISA plate and incubated at room temperature for 2 hours. [0297] The plate was washed 5X in PBST and blocked with 5% BSA diluted in TBST for 1 hour at 37ºC. [0298] The plate was washed 5X with PBST prior to addition of dilutions of the mEVs of P. histicola 1, P. histicola 2 and P. melanogenica at different particle concentration (8-point dilution starting at 1E10 p/well with a 5-fold dilution). The plate was incubated for 1 hour at 37ºC. [0299] The plate was washed 5X with PBST, and a biotinylated secondary detection antibody (02F09-02B04 clone) at 0.5 µg/ml was added incubated for 1hour at 37ºC. [0300] The plate was washed 5X with PBST, and 1:50,000 dilution of Streptavidin- HRP was added to the plate and incubated for 1 hour at 37ºC. [0301] The plate was washed 5X with PBST, and TMB substrate was added to the plate and incubated for 20 minutes in dark at room temperature. [0302] The reaction was stopped using 1N Hydrochloric acid and read at OD_450nm and OD652nm in a spectrophotometer. B. F. massiliensis 1 [0303] Based on the reactivity to F. massiliensis 1 mEVs and yield of the hybridomas, four clones were selected (01F08, 17E01, 14C10, and 16D07) for the subcloning process. Each selected clone was cultured by limiting dilution to ensure a monoclonal culture of cells producing the antibody of interest. The clones were allowed to multiply and grow. The supernatant of the subcloning process (at least three single colonies were selected for every hybridoma clone selected in the previous step) was screened for the specific antibody and its specificity to F. massiliensis 1 mEVs using the sandwich ELISA method. All combinations of the capture and detection antibody were tested using the following protocol. [0304] The capture antibody (all 11 subclones) at 0.5 µg/mL concentration was immobilized on a Nunc maxisorp ELISA plate and incubated at room temperature for 2 hours. [0305] The plate was washed 5X in PBST and blocked with 5% BSA diluted in TBST for 1 hour at 37ºC. [0306] The plate was washed 5X with PBST before adding dilutions of the of F. massiliensis 1 mEVs and negative control Megasphaera sp. at 2 µg/mL protein concentration. The plate was incubated for 1 hour at 37ºC. [0307] The plate was washed 5X with PBST, and a biotinylated secondary detection antibody (All 11 subclones) at 0.5 µg/ml was added incubated for 1 hour at 37ºC. Note: The subclones from the parent clone cannot be used as a pair. For example, when 01F08-02B04 subclone was used as a coating antibody, 01F08-02D11 cannot be used as a detection. [0308] The plate was washed 5X with PBST, and 1:10,000 dilution of Streptavidin- HRP was added to the plate and incubated for 1 hour at 37ºC. [0309] The plate was washed 5X with PBST, and TMB substrate was added to the plate and incubated for 20 minutes in the dark at room temperature. [0310] The reaction was stopped using 1N Hydrochloric acid and read at OD450nm and OD_652nm in a spectrophotometer. Quantitative Sandwich ELISA Procedure [0311] The capture antibody (e.g., P. histicola 1 mEVs specific 17B01-02G10 clone) at 0.5 µg/mL concentration was immobilized on a Nunc maxisorp ELISA plate and incubated at room temperature for 2 hours. [0312] The plate was washed 5X in PBST and blocked with 5% BSA diluted in TBST for 1 hour at 37ºC. [0313] The plate was washed 5X with PBST prior to addition of dilutions of the P. histicola 1 mEVs calibrator, and the unknown. The plate was incubated for 1 hour at 37ºC. [0314] The plate was washed 5X with PBST, and a biotinylated secondary detection antibody (e.g., P. histicola 1 mEVs specific 02F09-02B04 clone) at 0.5 µg/ml was added incubated for 1 hour at 37ºC. [0315] The plate was washed 5X with PBST, and 1:50,000 dilution of streptavidin- HRP was added to the plate and incubated for 1 hour at 37ºC. [0316] The plate was washed 5X with PBST, and TMB substrate was added to the plate and incubated for 20 minutes in dark at room temperature. [0317] The reaction was stopped using 1N Hydrochloric acid and read at OD_450nm and OD_650nm in a spectrophotometer. SPR Analysis of Binding Phenomena between Antibodies and mEVs [0318] Experiments were carried out on a Biacore T100 instrument, which uses the phenomenon of surface plasmon resonance (SPR) to monitor interactions between a ligand immobilized on the surface of a sensor chip and an analyte in solution passing over the sensor chip. The analysis allows real-time, label-free monitoring of binding phenomena and affinity between the ligand and the analyte. [0319] Experiments were performed using HBS-EP+ (Cytiva) as running buffer. The surface of a sensor chip derivatized with streptavidin for capture of biotinylated compounds was conditioned with three consecutive one-minute injections of 1 M NaCl in 50 mM NaOH before ligand immobilization. Ligands were dissolved in HBS-EP+ buffer at a concentration at 2.5 µg/mL and injected on flow cells 1 and 2 at a flow rate of 10 µL/min to reach an immobilization level of approximately 400 RU. The biotinylated monoclonal antibody (antibody 17B01-02G10) specific for mEVs of a Prevotella histicola strain, Prevotella Strain B 50329 (NRRL accession number B 50329; “P. histicola 1”), was immobilized on flow cell 2 (Fc2). Flow cell 1 (Fc1) was derivatized with a biotinylated mouse IgG1 kappa antibody (Invitrogen, Catalog # 13-4714-85) to serve as negative control (isotype control) and to correct for non-specific binding. [0320] mEVs from P. histicola 1 were diluted in HBS-EP+ to a protein mass concentration of 1, 2, 4, 8, 16, or 32 µg/mL and injected on Fc1 and Fc2 at a flow rate of 10 µL/min for 600 sec, followed by 900 sec of dissociation time. Surface regeneration was performed twice after every run with 10 mM glycine buffer at pH 2.5 injected at a flow rate of 30 ^L/min for 30 sec, followed by 30 sec of stabilization time. After surface regeneration, HBS-EP buffer was injected at a flow rate of 10 µL/min for 600 sec to serve as a blank. The average of three blank sensorgrams served for background subtraction to account for system drift. [0321] Subtraction of reference channel Fc1 from Fc2 was performed to account for non-specific interactions between ligands and analytes. [0322] A similar experiment was conducted with P. histicola 1 mEV drug substance (i.e., mEVs mixed with excipients) diluted to a protein mass concentration of 1, 2, 4, 8, 16, or 32 µg/mL. [0323] As a negative control, extracellular vesicles from a Harryflintia acetispora strain were diluted to a protein mass concentration of 1, 2, 4, 8, 16, or 32 µg/mL and binding to the antibodies immobilized on Fc1 and Fc2 was monitored. Example 2: P. Histicola 1 mEVs polyclonal antibody serum [0324] Indirect ELISA was used to detect increasing IgG levels in the serum from immunized mice at different time points. Increased IgG titers were observed for time points after immunization (Figure 1). Indirect ELISA was also used to assess the cross-reactivity of the polyclonal serum to mEVs from distinct species within the Prevotella genus and from genera other than Prevotella. The polyclonal antibody can also react with mEVs from some (but not all) species within the Prevotella genus (Figure 2). The polyclonal antibody reacted with mEVs from a different strain of Prevotella histicola, P. histicola 2 (ATCC designation number PTA-126140), and with mEVs of a strain of Prevotella melanogenica. [0325] Due to high cross-reactivity of a polyclonal antibody to other mEVs, monoclonal antibodies were developed against P. histicola 1 mEVs. Example 3: Indirect ELISA using monoclonal antibodies [0326] As shown in Figure 3, the 30 clones showed varying degrees of reactivity to the mEVs of P. histicola 1 and P. histicola 2 and little to no reactivity to mEVs from P. melanogenica. [0327] Based on the reactivity to P. histicola 1 and yield of the hybridomas, four clones were selected (02F09, 17B01, 17C10, and 17E05) for subcloning. Each selected clone was cultured by limiting dilution to ensure a monoclonal culture of cells producing the desired antibody of interest. A sandwich ELISA format was optimized using the subclones from 17B01 and 02F09 (see Example 1). The sandwich ELISA format increases the specificity of ELISA reactions as there are two antibodies (a capture/coating antibody and a detection antibody). By screening the clones in different orientations in sandwich ELISA, clone 17B01 was found to work best as a capture antibody and clone 02F09 as a detection antibody (Figure 4). [0328] The subclones of 17B01 and 02F09 antibody were screened using particle count of mEVs. Hybridoma clone 17B01-02G10 as the capture antibody and clone 02F09- 02B04 as the detection antibody were selected as the best sandwich antibody pair. These antibodies were analyzed to determine their amino acid sequences and their complementary determining regions (CDRs). While there was cross reactivity of P. histicola 1 mEV antibodies to P. histicola 2 mEVs, the sandwich ELISA method based on particle count distinguished between the two strains. Example 4: Quantitative SPR analysis of P. histicola 1 mEVs and P. histicola 1 mEVs in drug substance [0329] SPR analysis was carried out as described in Example 1. Negligible amounts of non-specific binding were observed for P. histicola 1 mEVs and the isotype control antibody immobilized on Fc1 (Figure 5). Concentration-dependent binding between the immobilized biotinylated monoclonal antibody 17B01-02G10 and the mEVs from P. histicola 1 after blank and isotype control subtraction was observed (Figure 6). Interactions between the antibody isotype control and the mEVs from P. histicola 1 drug substance were observed (Figure 7). [0330] Concentration-dependent binding was detected between the immobilized biotinylated monoclonal antibody 17B01-02G10 and the mEVs from P. histicola 1 drug substance after blank and isotype control subtraction (Figure 8). These data show the presence of excipients in P. histicola 1 drug substance does not prevent binding of the P. histicola 1 mEVs to the antibody. No binding was detected between the immobilized biotinylated monoclonal antibody 17B01-02G10 specific for P. histicola 1 mEVs (the ligand) and the extracellular vesicles from Harryflintia acetispora after blank and isotype control subtraction (Figure 9). Example 5: Sandwich ELISA analysis distinguishes between different Prevotella strain mEVs [0331] Sandwich ELISAs were performed as described above to determine if the assay was sensitive to distinguish between different strains of Prevotella histicola. mEVs from different strains of Prevotella (P. histicola 1, P. histicola 2, and P. melanogenica) were assayed. This sandwich ELISA format based on particle count distinguished between mEVs of the different strains of Prevotella histicola and did not generate false positive signals due to the presence of mEVs from P. melanogenica (Figure 10). Example 6: F. massiliensis 1 mEV polyclonal serum antibodies [0332] Polyclonal antibodies to F. massiliensis 1 mEVs were generated in New Zealand white rabbits as described in Example 1. Pooled serum from all the rabbits for each day were tested for increasing IgG levels using indirect ELISA (Figure 11). To increase the specificity of the serum, terminal serum (Day 90 serum), following the booster dose, was used to prepare purified total IgG using a Protein A purifying column. [0333] The cross-reactivity of the F. massiliensis 1 mEVs polyclonal serum to different mEVs from bacteria of the same and distinct genera and family was assessed in an indirect ELISA. The polyclonal antibody can also react with mEVs of F. massiliensis 2 (a second strain of F. massiliensis), P. histicola 1, H. acetispora, and Fae. prausnitzii (Figure 12). [0334] Due to high cross-reactivity of a polyclonal antibody to other mEVs, there was a need to generate antibodies specific to F. massiliensis 1 mEVs. To this end, monoclonal antibodies against F. massiliensis 1 mEVs were developed. Example 7: F. massiliensis 1 mEV monoclonal serum antibodies [0335] F. massiliensis 1 mEV monoclonal antibodies were prepared as described above in Example 1. Twenty-two (22) hybridoma clones were tested in indirect ELISA using the following protocol: ^ mEVs of F. massiliensis 1, F. massiliensis 2, Megasphaera sp., and H. acetispora are immobilized on a Nunc Maxisorp plate at 2 µg/mL protein concentration and incubated at room temperature for 2 hours. ^ The plate is washed 5X with PBST, blocked with 1% Casein and incubated for 1 hour at 37ºC. ^ The plate is washed 5X with PBST, supernatant is added at 0.5 µg/mL and incubated for 1 hour at 37ºC. ^ The plate is washed 5X with PBST, 1:10,000 of goat anti-mouse IgG is added and incubated for 1 hour at 37ºC. ^ The plate is washed 5X with PBST, and TMB substrate is added to the plate and incubated for 20 minutes in the dark at room temperature. ^ The reaction is stopped using 1N Hydrochloric acid and read at OD450nm and OD_652nm in a spectrophotometer. [0336] The 22 clones showed varying reactivity to the mEVs of F. massiliensis 1 and F. massiliensis 2. There was little to no reactivity to the mEVs of H. acetispora and Megasphaera sp. (Figure 13). [0337] Based on the reactivity to F. massiliensis 1 mEVs and yield of the hybridomas, four clones were selected (01F08, 17E01, 14C10, and 16D07) for the subcloning process. Each selected clone was cultured by limiting dilution to ensure a monoclonal culture of cells producing the antibody of interest. The clones were allowed to multiply and grow. The supernatant of the subcloning process (at least three single colonies were selected for every hybridoma clone selected in the previous step) was screened for the specific antibody and its specificity to F. massiliensis 1 mEVs using the sandwich ELISA method as described in Example 1. [0338] The combination of subclones of 14C10 (01C09, 02C06) as a capture antibody and subclones of 17E01(02B12 and 02G12) as a detection antibody worked well as a sandwich ELISA antibody pair without any background signal (Figures 14A, 14B). The other combinations reacted to Megasphaera sp. mEVs in the sandwich ELISA format. [0339] Four pairs of capture/coating and detection antibodies were then selected to characterize F. massiliensis 1 mEVs. They were 14C10-01C09 with 17E01-02B12 or 17E01-02G12 and 14C10-02C06 with 17E01-02B12 or 17E01-02G12. Particle-based sandwich ELISA distinguished F. massiliensis species (strains 1 and 2) from Megasphaera mEVs, as shown in Figures 15A-15D. Example 8: Quantitative Sandwich ELISA [0340] Four P. histicola 1 mEVs lyophilized batches (A124-C-Lyo-Exc 7A, A129- B-Lyo-Exc 7A, A142-B-Lyo-Exc7A and A138-A142 pool) were used to generate the calibrator (See, e.g., WO/2019/051381). Each batch was run separately and the data pooled together. The particle counts for all these batches were previously determined using NTA. 100 mg of each batch was reconstituted in 1 mL phosphate buffered saline (PBS) to get particle counts of 1.06 x 10¹² p/mL, 1.09 x 10¹² p/mL, 1.94 x 10¹² p/mL, and 1.28 x 10¹² p/mL respectively. The reconstituted samples were further diluted (2-fold) in assay diluent buffer (1% BSA in TBS buffer) to generate an 8 point standard curve spanning a range of 2 x 10⁹ p/mL to 1.56 x 10¹² p/mL. The test sample (labeled “unknown”) was diluted 1:1,000 from the stock. All samples (calibrators and unknown) were run in triplicates using the sandwich ELISA method described in Example 1 above. Linear regression (correlation coefficient = 0.95) on the OD values of the calibrators (expressed as Mean ^ SD, n = 12) was used to generate a single standard curve. The concentration (p/ml) of the unknown was interpolated from the standard curve using the OD value as shown in Figure 16. [0341] The assay can be used to determine the particle count of P. histicola 1 mEVs in drug substance “DS” (mEVs + excipients e.g., lyophilized batches) and/or drug product “DP” (dosage form containing mEVs) without any interference from excipients and media components, as the antibodies are specific to extracellular vesicles alone. This methodology was not impacted by DS/DP excipients or inaccuracy of measurement due to non-EV associated protein(s) in the DS/DP. [0342] The assay exhibits linearity with a defined Limit of Detection (LOD) of 1.5 x 10⁷ p/mL and a Limit of Quantitation (LOQ) of 2 x 10⁹ p/mL. Example 9: Detection and quantification of P. histicola 1 mEVs in blood [0343] Subjects are orally dosed with a composition comprising P. Histicola 1 mEVs, have blood drawn prior to mEVs administration (day 0) and at various time points post oral administration. The blood sample is processed and evaluated for the presence of P. Histicola 1 mEVs. [0344] The capture antibody (17B01-02G10 clone) at 0.5 µg/mL concentration is immobilized on a Nunc maxisorp ELISA plate and incubated at room temperature for 2 hours. [0345] The plate is washed 5X in PBST and blocked with 5% BSA diluted in TBST for 1 hour at 37ºC. [0346] The plate is washed 5X with PBST prior to addition of a blood sample. The plate is incubated for 1 hour at 37ºC. [0347] The plate is washed 5X with PBST, and a biotinylated secondary detection antibody (02F09-02B04 clone) at 0.5ug/ml is added incubated for 1hour at 37ºC. [0348] The plate is washed 5X with PBST, and 1:50,000 dilution of Streptavidin- HRP is added to the plate and incubated for 1 hour at 37ºC. [0349] The plate is washed 5X with PBST, and TMB substrate is added to the plate and incubated for 20 minutes in dark at room temperature. [0350] The reaction is stopped using 1N Hydrochloric acid and read at OD_450nm and OD_652nm in a spectrophotometer. [0351] The concentration (p/ml) of the mEVs in the blood sample is interpolated from the standard curve using the OD value as described in Example 8. Example 10: Capture and purification of P. histicola 1 mEVs from fermentation media [0352] A solution of P. Histicola 1 mEVs is incubated with biotinylated monoclonal antibodies 17B01-02G10 specific for P. histicola 1 mEVs at room temperature, for 20 minutes to 2 hours while mixing. The solution is then added to a microcentrifuge tube containing pre-washed strepavidin magnetic beads and incubated at room temperature for 1 hour with mixing. The beads are then collected with a magnetic stand and rinsed. P. histicola 1 mEVs is released from the beads using a standard elution buffer (e.g., recommended by the manufacturer of the beads). If needed, eluted P. histicola 1 mEVs can be further purified by buffer exchange or ultracentrifugation. Example 11: Purification of P. histicola 1 mEVs using mAb + derivatized beads [0353] Monoclonal antibodies 17B01-02G10 specific for P. histicola 1 mEVs are added to a suspension of commercially available magnetic or agarose beads derivatized with protein A or protein G. The antibodies are then chemically crosslinked to the beads to avoid antibody release. A solution of P. Histicola 1 mEVs is incubated with the derivatized magnetic or agarose beads. After incubation, the derivatized magnetic beads are recovered using a magnetic stand, while the agarose beads are recovered by ultracentrifugation. Beads are then washed to remove unbound material. P. histicola 1 mEVs are released using a standard elution buffer, for example, an elution buffer recommended by the manufacturer of the beads. If needed, eluted P. histicola 1 mEVs can be further purified by buffer exchange or ultracentrifugation. Example 12: Purification of P. histicola 1 mEVs using a column [0354] Monoclonal antibodies 17B01-02G10 specific for P. histicola 1 mEVs are immobilized on commercially available protein A, protein G column, streptavidin column, spin-column, or resin. A solution containing P. Histicola 1 mEVs is passed through the column and washed with one or more column volumes of binding buffer. After washing, P. Histicola 1 mEVs are recovered with an elution buffer. Example 13: Flow cytometry with mEVs conjugated with aldehyde/sulfate latex beads plus antibodies [0355] A solution of 9.2E11 particles (p)/ml P. histicola 1 mEVs was diluted 1:100 with PBS (10 ^L solution + 990 ^L PBS) to obtain a 9.2E9 p/ml suspension. [0356] 100 ^L of a 9.2E9 p/ml suspension of P. histicola 1 mEVs were incubated with 1 ^L of the aldehyde/sulfate latex beads 4 ^m 4% w/v and incubated for 15 min at room temperature. [0357] 10 mg BSA (Sigma, A2058, Lot SLCG7252) were dissolved in 10 mL PBS to provide a 0.1% w/v solution.1 mL of this solution was added to the P. histicola 1 mEVs derivatized with the beads and the sample was incubated overnight on rotation. Beads- coupled- P. histicola 1 mEVs were pelleted by centrifugation at 1,500 rpm (2,000 g) for 10 min, washed with 1 mL PBS+BSA and pelleted again at 2,000 rpm for 10 min. [0358] Biotinylated primary antibody 17B01-02G10 specific for P. histicola 1 mEVs and APC (Allophycocyanin) streptavidin were diluted 1:10 with PBS (1 µL of reagent was added to 9 µL of PBS).1 µL of the diluted biotin-mAb antibody was added to 100 µL of P. histicola 1 mEVs conjugated to aldehyde/sulfate latex beads at a final dilution of 1:1000 v/v and incubated for 45 min (20-30 min can also be sufficient) at 4ºC. [0359] The excess antibody was washed off by centrifugation at 1,500 rpm (2,000 g) for 10 min. The supernatant was discarded, 100 µL of PBS and 1 µL of streptavidin were added and the solution was incubated for 45 min (20-30 min can also be sufficient) at 4ºC, in the dark. [0360] The excess antibody was washed off by centrifugation at 1,500 rpm (2,000 g) for 10 min. The sample was resuspended in 100 µL of PBS to provide a 2.3E9 p/mL suspension. The sample was diluted 1:100 to provide a 2.3E7 p/mL suspension for flow cytometry. Samples were stored initially at -20ºC for 1 hr, then at 4ºC. [0361] Samples were analyzed using a Attune NxT flow cytometer and analyzed by FlowJo. Underivatized aldehyde/sulfate latex beads were used to select optimal instrument settings and gates. Gates were set to exclude background corresponding to debris usually present in buffers. [0362] The result of the flow cytometry is show in Figure 17. A positive APC signal was detected. INCORPORATION BY REFERENCE [0363] All publications, patents, patent applications and sequence accession numbers mentioned herein are hereby incorporated by reference in their entirety as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference. In case of conflict, the present application, including any definitions herein, will control. EQUIVALENTS [0364] Those skilled in the art will recognize or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments described herein. Such equivalents are intended to be encompassed by the following claims.

Claims

CLAIMS We claim: 1. A method of detecting microbial extracellular vesicles (mEVs) in a sample, quantifying mEVs in a sample, and/or identifying the genus, species, and/or strain of bacteria from which mEVs in a sample are obtained and/or derived, the method comprising: (a) contacting the sample comprising the mEVs with a first antibody that specifically binds to an antigen on the mEVs, optionally wherein the first antibody is detectably labeled; and (b) detecting the binding of the first antibody to the mEVs, thereby detecting, quantifying, and/or identifying the genus, species, and/or strain of bacteria from which the mEVs are obtained and/or derived.

2. The method of claim 1, wherein step (a) further comprises contacting the sample comprising the mEVs with a second antibody that specifically binds to an antigen on the mEVs, optionally wherein the second antibody is detectably labeled, and step (b) further comprises detecting binding of the second antibody to the mEVs.

3. The method of claim 1 or claim 2, wherein the binding is detected in step (b) using ELISA, flow cytometry, or microscopy.

4. The method of any one of claims 1-3, wherein the first and/or second antibody comprises a heavy chain CDR1 of SEQ ID NO: 3, a heavy chain CDR2 of SEQ ID NO: 4, and/or a heavy chain CDR3 of SEQ ID NO: 5.

5. The method of claim 4, wherein the first and/or second antibody comprises (i) a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 2 or wherein the antibody comprises a heavy chain variable region of SEQ ID NO: 2, and/or (ii) a heavy chain having a sequence at least 95% identical to SEQ ID NO: 1 or wherein the antibody comprises a heavy chain of SEQ ID NO: 1. 128

6. The method of claim 4 or claim 5, wherein the first and/or second antibody comprises a light chain CDR1 of SEQ ID NO: 8, a light chain CDR2 of SEQ ID NO: 9, and/or a light chain CDR3 of SEQ ID NO: 10.

7. The method of any one of claims 4-6, wherein the first and/or second antibody comprises (i) a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 7 or wherein the antibody comprises a light chain variable region of SEQ ID NO: 7, and/or (ii) a light chain having a sequence at least 95% identical to SEQ ID NO: 6 or wherein the antibody comprises a light chain of SEQ ID NO: 6.

8. The method of any one of claims 1-7, wherein the first and/or second antibody comprises a heavy chain CDR1 of SEQ ID NO: 13, a heavy chain CDR2 of SEQ ID NO: 14, and/or a heavy chain CDR3 of SEQ ID NO: 15.

9. The method of claim 8, wherein the first and/or second antibody comprises (i) a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 12 or wherein the antibody comprises a heavy chain variable region of SEQ ID NO: 12, and/or (ii) a heavy chain having a sequence at least 95% identical to SEQ ID NO: 11 or wherein the antibody comprises a heavy chain of SEQ ID NO: 11.

10. The method of claim 8 or claim 9, wherein the first and/or second antibody comprises a light chain CDR1 of SEQ ID NO: 18, a light chain CDR2 of SEQ ID NO: 19, and/or a light chain CDR3 of SEQ ID NO: 20.

11. The method of any one of claims 8-10, wherein the first and/or second antibody comprises (i) a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 17 or wherein the antibody comprises a light chain variable region of SEQ ID NO: 17, and/or (ii) a light chain having a sequence at least 95% identical to SEQ ID NO: 16 or wherein the antibody comprises a light chain of SEQ ID NO: 16.

12. The method of any one of claims 1-11, wherein the mEVs are conjugated to latex beads prior to step (a), optionally wherein the latex beads are super active latex beads, optionally wherein the super active latex beads are aldehyde/sulfate beads.

13. The method of any one of claims 1-12, wherein first antibody is tethered to a surface, optionally wherein the surface is a biochip, microwell, bead, column, or a membrane.

14. The method of claim 13, wherein the mEVs are captured on the surface by the first antibody, optionally wherein the second antibody binds to the captured mEVs.

15. The method of claim 14, wherein step (b) further comprises contacting the second antibody with a detectably labeled third antibody specific for the second antibody and further comprises detecting the detectable label.

16. The method of claim 13, wherein the second antibody is biotin labeled and step (b) further comprises contacting the second antibody with a streptavidin-labeled detectable label and further comprises detecting the detectable label.

17. The method of any one of claims 1-16, wherein the mEVs are secreted mEVs (smEVs) or wherein the mEVs are processed mEVs (pmEVs).

18. The method of any one of claims 1-17, wherein the mEVs are derived from bacteria of the genus Prevotella, optionally wherein the mEVs are derived from bacteria of the species Prevotella histicola, optionally wherein the mEVs are derived from bacteria of the strain Prevotella Strain B 50329.

19. The method of any one of claims 1-17, wherein the mEVs are derived from bacteria of the genus Fournierella, optionally wherein the mEVs are derived from bacteria of the species Fournierella massiliensis, optionally wherein the mEVs are derived from bacteria of the strain Fournierella massiliensis Strain A (ATCC Deposit Number PTA-126696).

20. An antibody comprising a heavy chain CDR1 of SEQ ID NO: 3, a heavy chain CDR2 of SEQ ID NO: 4, and/or a heavy chain CDR3 of SEQ ID NO: 5.

21. The antibody of claim 20, wherein the antibody comprises (i) a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 2 or wherein the antibody comprises a heavy chain variable region of SEQ ID NO: 2, and/or (ii) a heavy chain having a sequence at least 95% identical to SEQ ID NO: 1 or wherein the antibody comprises a heavy chain of SEQ ID NO: 1.

22. The antibody of claim 20 or claim 21, wherein the antibody comprises a light chain CDR1 of SEQ ID NO: 8, a light chain CDR2 of SEQ ID NO: 9, and/or a light chain CDR3 of SEQ ID NO: 10.

23. The antibody of any one of claims 20-22, wherein the antibody comprises (i) a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 7 or wherein the antibody comprises a light chain variable region of SEQ ID NO: 7, and/or (ii) a light chain having a sequence at least 95% identical to SEQ ID NO: 6 or wherein the antibody comprises a light chain of SEQ ID NO: 6.

24. An antibody comprising a heavy chain CDR1 of SEQ ID NO: 13, a heavy chain CDR2 of SEQ ID NO: 14, and/or a heavy chain CDR3 of SEQ ID NO: 15.

25. The antibody of claim 24, wherein the antibody comprises (i) a heavy chain variable region having a sequence at least 95% identical to SEQ ID NO: 12 or wherein the antibody comprises a heavy chain variable region of SEQ ID NO: 12, and/or (ii) a heavy chain having a sequence at least 95% identical to SEQ ID NO: 11 or wherein the antibody comprises a heavy chain of SEQ ID NO: 11.

26. The antibody of clai 24 or claim 25, wherein the antibody comprises a light chain CDR1 of SEQ ID NO: 18, a light chain CDR2 of SEQ ID NO: 19, and/or a light chain CDR3 of SEQ ID NO: 20.

27. The antibody of any one of claims 24-26, wherein the antibody comprises (i) a light chain variable region having a sequence at least 95% identical to SEQ ID NO: 17 or wherein the antibody comprises a light chain variable region of SEQ ID NO: 17, and/or (ii) a light chain having a sequence at least 95% identical to SEQ ID NO: 16 or wherein the antibody comprises a light chain of SEQ ID NO: 16.

28. A nucleic acid molecule comprising a sequence encoding a heavy chain or light chain of an antibody of any one of claims 20-27.

29. A vector comprising the nucleic acid of claim 28.

30. A host cell comprising the nucleic acid of claim 28 or the vector of claim 29.

31. A method of purifying bacteria or microbial extracellular vesicle (mEVs) from a solution, the method comprising: (a) contacting the solution comprising the bacteria or mEVs with an antibody or antigen binding fragment thereof of any one of claims 20-27; and (b) eluting the bacteria or mEVs from the antibody or antigen binding fragment thereof, thereby purifying the bacteria or mEVs from the solution.