CA2227317A1 - Method and apparatus for automatically inoculating culture media with bacterial specimens from clinical specimen containers - Google Patents

Abstract

This invention relates to a method and apparatus for automatically streaking bacterial samples on the surface of culture media plates in programmable patterns to effect dilution and produce isolated bacterial colonies.

Description

TITLE:: METHOD AND APPARATUS FOR AUTOMATICALLY INOCULATING
CULTURE MEDIA WITH BACTERIAL SPECIMENS FROM
CLINICAL SPECIMEN CONTAINERS.
FIELD OF THE INVENTION
This invention relates to an apparatus and method for automatically transferring bacterial specimens from specimen containers to the surface of culture medium plates, and to streaking such bacterial samples in programmable patterns to produce isolated bacterial colonies. In particular, it provides for the precise deposition of an inocul.ant at a specific location on the surface of a culturing medium, and the subsequent re-entry of a streaking tool at this name location to effect streaking. It further the provides a versatile system for varying the streaking procedure in accordance with the specimen being treated. This invention also relates to an apparatus and method for automatically removing the top of either "jar-type" specimen container or a "swab-type" container while simultaneously identifying the specimen.
BACKGROUND TO THE INVENTION
The isolation and identification of a sample of a bacterial specimen has for many years involved the inoculation of the: sample onto a culture medium. The type of culture medium used and the method by which it is placed on the culture medium depends on the type of specimen being handled.

This invention relates to two types of specimen containers. One type of specimen container, the "swab-type", consi:~ts of a stylus- or wand-like stem attached to a cap remov<~bly fitted onto a separate, test-tube like container.
A swab fixed at the opposite end of the stem from the cap is coated with and carries the bacterial specimen during transfer to the cultivating medium. The other type of specimen container, the "jar-type", consists of a jar- or bottle-like vessel. containing a liquid specimen, such as urine, a portion of wh:ich is to be transferred to inoculate the cultivating medium.
The receptacle containing the swab is typically a transparent tube having a closed end and an open end providing a narrow mouth. The swab shaft carries its absorbent pad -the swab- at the outer end of the stem remote from the cap end.
While the stem extends into the tube from the cap when the cap is in place on the tube, variations in manufacturing may cause the stem to be deflected sideways. Hence, upon removal of the swab stem from the tube, the stem may deflect from alignment with the central axis of the cap causing the displacement of the swab tip sideways. The precise location of the swab relative to the cap and the axis of the cap will then be unknown.
Inoculation from a "swab-type" container requires removal of the cap with the stem and swab attached from the

2 recepi~acle and rolling the swab end (which is coated with the specimen) over a portion of the surface on the culture medium.
This i~ransfer must occur at a specific deposit location and the sides of the swab should be equally exposed to the surface of thE~ cultivating medium during transfer of bacteria to the deposit location. If the swab stem is bent, this operation is difficult to effect.
After inoculation occurs the swab is normally returned to its original container. In doing so the swab must be aligned with the mouth of the test-tube to prevent contamination of the exterior portion of the tube. This alignment must be arranged even when the swab stem is bent.
Inoculation from a "jar-type" container requires removal of the cap, extraction of a specified amount of liquid:, e.g. urine, and placement of an amount of liquid onto the deposit location on the culture medium's surface. The container with its remaining liquid is then recapped and conveyed away for storage.
Inoculation from a "jar-type" container requires identification of the specimen by reading markings on the outside surface of the container, removal of the cap, extraction of a specified amount of urine and placement of that amount onto a defined area on the culture medium. This procedure is time consuming, inconsistent and biohazardous.
Automating the entire procedure would address a11 three of

3 these concerns. Two critical parts of the inoculating process for the "jar-type" specimen container are the uncapping of the specimen container and the reading of the data imprinted on the container.
The isolation and identification of a specimen requi~__~es that the specimen sample be distributed or spread over the culture medium in a one of several prescribed patterns that is correlated to the specific specimen. These patterns must provide an increasing dilution of the sample and are effected by a streaking tool. Once so streaked the prepared medium plates can then be incubated to promote bacterial growth. This bacterial growth can then be examined or subjected to further tests for isolation or identification of they bacteria types) present in the specimen.
Proper preparation of the media plates is biohazardous, time consuming and difficult to perform manually in a ~~onsistent manner. It is also difficult to maintain consistency between the techniques used by different technicians or even between different samples prepared by the same technician at different times.
An object of this invention is therefore to provide a method and apparatus for inoculating medical specimens from either the ~swab-type" or "jar-type" containers onto culture media which closely simulates the effect of established manual

4 procedures, but with improved consistency, accuracy and safety.
A further objective is to provide a method in which a specimen swab, e.g. an elongate element, which is somewhat bent from its nominal position may be properly applied to the surface of a cultivating medium and then be reinserted into its originating receptacle consistently and accurately.
A further object of this invention is to provide a method and apparatus for streaking bacterial samples in programmable patterns corresponding to the actual specimen being evaluated, which streaking closely simulates the effect of established manual procedures, but with improved consi:~tency, accuracy and safety.
Yet a further objective is to provide an efficient method and apparatus in which the cap of a jar-type container may be removed in parallel with reading data that has been imprinted, encoded or otherwise embedded on the container. An additional objective is to provide a method and apparatus in which the existence of a sufficient amount of liquid specimen in the container may be verified.
The invention in its general form will first be described, and then its implementation in terms of specific embodiments will be detailed with reference to the drawings following hereafter. These embodiments are intended to demonstrate the principle of the invention, and the manner of

5 its implementation. The invention in its broadest and more speci:Eic forms will then be further described, and defined, in each of the individual claims which conclude this Speci:Eication.
SUMMA~2Y OF THE INVENTION
A preferred embodiment of this invention provides an automated overall specimen container transport, handling and inoculating system which integrates and improves standard proceclures and techniques for transferring bacteria to a cultivating medium, followed by streaking of such bacteria onto ~:uch medium.
The mechanism dispenses culture media as called for by the specimen's embedded data and identifies or labels each dispensed container of media so that it can be correlated with its corresponding specimen. A sample of the bacterial specimen on a specimen carrier e.g. , a swab or pipette, is then transpersed to the culture medium by a specimen sample positioning system or "specimen positioning system".
Streaking is thereafter effected in accordance with the procedure appropriate for each specific specimen.
A special feature of the invention is that a specimen positioning system which is computer controlled is used to convey the specimen from its original container to a deposit location on the culture medium. A computer controlled

6 streaiking tool carried by a streaking mechanism is then directed to the same deposit location based upon digitally stored data corresponding to the precise position of such deposit location. The streaking tool then enters the culture medium and effects streaking in accordance with the pattern suited for the specific specimen with which the culture medium has bE:en inoculated.
The specimen positioning system brings the specimen carrier with its bacterial sample in contact with the culture medium in a controlled manner which ensures that the bacteria are deposited at the deposit location. For "swab-type"
specimens comprising a stylus- or wand-like swab stem attached to a cap and carrying a swab coated with the bacterial specimen, the swab is so "fixtured" that when it is brought into contact with its corresponding culture medium, the transfer of bacteria occurs at the deposit location in the correca manner.
To achieve such fixturing of the swab according to one feature of the invention, a capped swab-containing receptacle is first placed into a holding fixture by a robot manipulator. The same manipulator then grasps the cap and withdraws it and the attached swab stem from the mouth of the receptacle. The swab and swab stem are then presented to a tip location device. The exact location of the swab located at the stem tip and its orientation with respect to the cap's

7 position is determined by a visual examination effected by the tip location device. This exact tip location is then stored in a digital memory to subsequently be used to control the specimen positioning system in positioning the swab on the culture medium at the deposit location in order to properly inocu7!ate that medium. Then the specimen positioning system is usE:d to reinsert the swab into the receptacle, again using the digitally stored data defining the location of the swab at the stem tip to ensure that the swab passes into the mouth of its container without contaminating its rim or exterior surface.
In one embodiment, the swab tip is located using a camera and a single back-lighted surface. A 90~ rotation about the axis of the element is effected and two images are taken by the camera to establish the location of the swab tip.
In another embodiment, the swab tip is located using a single camera. image frame, two mirrors, and two back-lighted surfaces whereby two separate views of the swab tip are effected simultaneously. In yet another embodiment, a laser range camera may be used to scan and establish the location of the swab tip.
The swab tip is then carried by the specimen positioning system to the deposit location whereat the outer surface of the swab is rolled against the surface of the culture medium to transfer bacteria to the deposit location.

8 During this transfer, the swab is fixtured to maintain the required degree of contact with the culture medium surface by the acaion of the specimen positioning system in adjusting the location of the cap laterally while the cap is being rotated.
This adjustment is effected using the data for the location of the swab tip with respect to the cap, as stored in the digital memory.
Rather than so controlling the position of the cap while it is being rotated, the cap may be rotated at a stationary location if the swab tip is mechanically fixtured to ens>ure that it is positioned along the axis of rotation of the cap. This may be effected by extending a guide, such as a wire, with a loop, from the specimen positioning system so that the loop guides the swab tip into alignment with the axis of roi~ation of the cap during transfer of bacteria to the culture medium.
For "jar-type" containers, once its cap is removed, the specimen positioning system uses a pipetting tool as the specimen sample carrier to extract a volume of liquid from the open container and then deposit a volume of this liquid onto the surface of the culture medium at the deposit location.
Again, the specimen carrier --the pipetting tool-- is so fixtured that the robot manipulator places the specimen precisely at the deposit location. As previously described,

9 the position of the deposit location in space is recorded in a digital memory for subsequent use in further operations.
To present the jar-type containers to the specimen positioning system, a container manipulating device grasps the cap oi= the specimen container while the container is rotated by a rotating jar holder. The container manipulating device raise:a and removes the cap of the specimen container to one side once the rotating holder for the container has rotated it sufficiently so as to cause the cap and the receptacle to disengage. During this rotational motion, a scanning device located to one side of the holder/reader platform may conveniently read specimen- identifying indicia that has been previously imprinted, encoded or otherwise embedded on the side of the specimen container. A similar procedure may also be provided for reading indicia carried on the side of tubes containing swabs.
Provision is included for verifying the amount of specimen in the container. Provision is also provided for replacing the cap on the receptacle of the specimen container after the sample has been extracted.
As a particularly convenient arrangement, a jar-type container may be delivered to its lid-opening station on a conveyor, and the removal of the list and extraction of a specimen sample may be effected with the jar container remaining on and supported by the conveyor.

Once a sample of bacteria has been transferred to the deposit location, streaking is then effected by a strealting tool which is carried by the streaking mechanism to the deposit location. The control system for the streaking tool uses digitally stored data in order to carry the strealcing tool to the deposit location. The streaking pattern then affected is computer controlled to correspond with the identity of the specimen as obtained from the specimen conta~:ner.
The streaking apparatus of the invention with its computer control system is versatile and may adopt a full range of streaking patterns. This feature, combined with the capacity to accept specimens in differing types of containers renders the apparatus of the invention highly versatile.
The foregoing summarizes the principal features of the invention and some of its optional aspects. The invention may be further understood by the description of the preferred embodiments, in conjunction with the drawings, which now follow.
SUMMARY OF THE FIGURES .
Figure lA is a pictorial view of a combined inoculation and streaking apparatus for accepting samples in both swab-type and jar-type container formats.

Figure 1B is a pictorial view of an inoculating and streaking apparatus for handling jar-type urine samples.
Figure 1C is a pictorial view of an inoculating and streal~;ing apparatus for handling swab-type specimens.
Figures 2 through 6 are successive pictorial depict:ions of the removal (Figs. 2, 2A, 3), viewing (Fig. 4), and reinsertion of a swab in a tube (Figs. 5, 6).
Figure 7 is a pictorial depiction of a video camera viewing a swab suspended by a robotic gripper against a back lit surface panel.
Figure 8 is a plan view of the geometry for the extracaion of the location of the swab tip being viewed in Figure. 7.
Figure 9 is a pictorial depiction of a video camera viewing a swab suspended by a robotic gripper against a series of mirrored rear panels.
Figure 10 is a plan view of the geometry for the extraction of the location of the swab tip being viewed in Figure 9.
Figure 11 is a pictorial view of a laser/ranger video camera extracting the location of a swab tip in space.
Figure 12 is an isometric view of a "jar-type"
specimen container carrying identifying indicia on its side.

Figure 13 is an isometric view of part of one form of uncapping and data-reading apparatus for use with a jar-type ~~ontainer.
Figure 14 is an isometric view of the uncapping and data reading apparatus of Figure 13 with the lid grasped by a lid holder and the capped jar body held in place by the jar manipulating device.
Figures 15-17 are sequential isometric views of the uncapping and data reading apparatus of Figure 13 as the jar is uncapped and the data is read.
Figure 18 is a pictorial view of jar-type containers being delivered on a conveyor to a de-capping station.
Figure 19 is a plan view of Figure 18.
Figure 20 is an isometric view of the delivery of culture medium dishes to the inoculation location of the streal~:ing apparatus .
Figure 21 is an isometric view of the inoculation location of Figure 20 with the streaking mechanism in position over the exposed culture medium to effect streaking.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring generally to the drawings, FIGS. 1, 2, 3 and 20 illustrate the automated system having a conveyor system 1 for transporting specimen containers 2 into the system. The manipulating device li in the form of a robotic arm is used to grasp a specimen container 2 and move it in front of a specimen identification device 4. Electronic data from a label 209 on the specimen container read by the specimen identification device 4 is used to determine the type of culture medium plate 9 to be ejected from the plate dispenser 5.
The plate transport systemwl0 carries the culture medium plate 9 to the plate identification device 6. The manipulating device 11 places the specimen container into either- a " swab-type" holder 7 or a " j ar-type" holder 8 . The manipulating device 11 removes the cap from the specimen contap!ner. A "swab-type" stem is presented to a tip location device' 12 and then the culture medium plate 9 is inoculated.
A "jar-type" specimen will have a specified amount of liquid extracaed and inoculated onto the culture medium plate 9.
Handling of a swab-type container is shown in Figures 2 and 2A wherein the cap 22 and swab stem 21 are depicted, initially as in, and then being removed from the test-tube receptacle 20. Figure 3 shows the cap 22 and swab stem 21 entirely removed from the test-tube receptacle 2o and demonstrates the possible tip 21A displacement of the swab stem 21.
Figure 4 shows the cap 22 and swab stem 21 as presented to a camera-based tip location device 30. Figure 5 shows the cap 22 and swab stem 21 with the tip 21A of the swab stem 21 being centred above the open end of the test-tube recepi~acle by the end effector of the manipulating device 11.
In Figure 6 the cap 22 and swab stem 21 have been completely replaced in the test-tube receptacle 20.
Figure 7 shows the perspective view of the double snapshot tip location setup. This embodiment consists of the manipulating device 11 which grasps the cap 22 attached to one end of the swab stem 21. The manipulating device 11 moves the swab ;stem 21 to a position between a camera 30 and a back light panel 40. The camera 30 and back light panel 40 are rigidly fixtured by a mounting bracket 50. The first snapshot is taken by the camera 30, the manipulating device 11 rotates the ca.p 22 and swab stem 21 through 90~ about the long axis of the carp 22, and then the second snapshot is taken.
Figure 8 shows the geometric layout of the double snapshot tip location setup. The pertinent angles and distances are defined and the accompanying equations can be found in Equation Set 2 included hereafter.
Figure 9 shows a perspective view of the single snapshot tip location setup. This embodiment consists of a manipulating device 11 which grasps the cap 22 attached to one end of the swab stem 21. The manipulating device il moves the swab stem 21 to a position between a camera 30 with dual back light backlit panels, 40,41 mounted on either side of the camera 30, and two mirrors, 60,61 positioned to form an is A
Equation Set 1:
11'= The nominal elongate element tip pusition.
P~= Snapshot 1 elongate element tip positron.
P2= Snapshot 2 elongate element tip position.
tan a= =t ; tan ~3-obj obj a = d tan ~i ; b = d tan a g = tan a ; ~ = tan (3 a+c b+g c = a(tan a+b)tan ~3 ~ a = b 1- tan cxtan p +g j= c+c Equation Set 2 i a= tan- i A ; (~= tan- ~ B
im im, y= 135-3 ; b= 135-a 90-2cc >1=90-2~3 ;

8= 90+a ;

Iri i-j ; h= obj-I

d= sin45Xobj sin~5xobj , =

sin8 c sing sint3xc sin~xd _ i= ~ _ -.-sin~ ~ sin8 kxsin(90-a ) _ sin(a+(3)' P= The lip position ~3<a; P= (h+ g cos(90-~3 ), -g sinf90-~i ) (~>a; P= (h+g cos(90-~3 ), g sin(90-~3 ) l5 enclo:~ure around the swab stem 21. The mirrors are angeled to each other at 90~ . The camera 30 is placed such that its optical axis bisects the angle formed by the two mirrors 60, 61. Back light panel 41 is placed to form a 90~ angle with mirror 61 and back light panel 40 is placed to form a 90~
angle with mirror 60. The back light panels 40,41 must be narrow enough to leave a gap through which the camera 30 can view t:he mirrors 60, 61.
Figure 10 shows the geometric layout of the single snapshot tip location setup. The pertinent angles and distances are defined and the accompanying equations can be found in Equation Set 2.
Figure 11 shows a perspective view of the alternate laser range camera tip location setup. This embodiment consists of a manipulating device 11 which grasps the cap 22 attached to one end of the swab stem 21. The manipulating device 11 moves the swab stem 21 to a position in front of the laser range scanning camera 70. The laser range camera 70 is mounted on a linear slide 51 which is attached to a mounting bracket 50A. The linear slide 51 moves the laser range scanning camera 70 vertically while it collects data on range to the swab stem 21 which is compiled into a profile of the element tip. An alternative setup would have the camera 70 rigidly attached to the mounting bracket 50A and the scan would be accomplished by having the manipulating device 11 move the swab stem 21 with a straight line motion in the vertical direction.
Figure 12 illustrates a "jar-type" specimen container having a jar- or bottle-like vessel or receptacle 210, a separate cap 211 which may be affixed to the receptacle and an area 209 which has been imprinted, encoded or otherwise embedded with pertinent information regarding the specimen.
Figure 13 illustrates the holder/reader apparatus with the motor enclosure 212, the three slender grasping fingers 213, 214 and 215 and the container platform 216. The scanner device 218 is mounted on the support bracket 217.
Figure 14 illustrates how the cap 211 of the specimen container is grasped by the manipulator device 219 and placed on the container platform 216. The grasping finger's 213, 214 and 215 close about the container receptacle 210.
Figures 15-17 illustrate the rotational motion of the platform 216 and fingers 213, 214, 215 which cause the receptacle 210 to turn as well. Once the cap 211 and container 210 are disengaged, the manipulating device 219 moves 'the cap 211 with a positive vertical motion allowing the cap 211 and receptacle 210 to become separated. At the same time, the rotational motions of the receptacle 210 will cause the imprinted area 209 to be presented to the window 220 reading device 218 at some point during the revolution to effect recordal of the indicia thereon. The liquid specimen contained within the jar 210 may then be sampled to inoculate a culture medium.
An alternate decapping mechanism for jars is shown in Figures 19 and 20.
A jar 210 carried on a conveyor 400 is delivered to a reading station 411 where the jar 210 is grasped by four rollers 406, one of which is driven by motor 402. As the jar 210 i;s rotated by the powered roller 406, the indicia 209 carriEad on its side are read by the reader 403. Throughout rotation the jar 210 remains on the conveyor 400.
The j ar 210 is then advanced by the j ar conveyor 400 to a de-capping station 412. There rollers 405 again grasp the jar 210 while a cap-holding mechanism 407 grasps the cap 211. One of the rollers 405 driven by motor 401 rotates the jar body while the cap 211 is held against rotation by the cap-holding mechanism 407. Once sufficient rotation has occurred to effect disengagement, the cap 211 is raised from the jar 210 and the cap-holding mechanism 407 retires from the de-capping site 412 carrying the cap 211 with it. This exposes the specimen contents of the jar 210 for removal of a sample.
Figure 20 illustrates the delivery of a culture medium container (in the form of a plate 310) positioned on a conveyor 340 to an inoculation and streaking station 341. The culture medium plate 310 is inverted on the conveyor 340 with its lid on the downward side. Two clamping arms 315,316 rotationally transfer the plate 310 containing an agar or simil<~r coating to the inoculation and streaking station 341 with :its agar-coated surface upwardly exposed.
At the inoculation and streaking station 341 rails 311,3.L2 support a cross motion beam 313 which, in turn, carriE~s the streaking tool 314. The rails 311,312 provide for effecting motion in the +/- X direction. Cross motion beam 313 supports the streaking tool 314 and provides for motions in the +/- Z direction.
Once a culture medium plate 310 has been inoculated at the deposit location 342, a sterile tip portion (not shown) of the' streaking tool 314, is brought into contact with the inoculated spot on the culture plate 310. Since the streaking tool 314 is mounted on an actuated platform that can produce relative motion between the arm 313 and the plate 314 in two independent directions, it is made to move through a user-defined, two-dimensional pattern that has been programmed into the streaking actuator's computer-managed control unit 344.
The tip of the streaking tool 314 enters the surface of the: culture medium at precisely the deposit location 342 based on the stored data carried within the computer control unit 344. This data corresponds to the location whereat the manipulator 11 effected deposit of the bacterial specimen which is also stored in the memory of the computer control unit. Once the spreading head makes contact with the culture medium the appropriate streaking pattern is executed in , response to commands from the computer control unit 344.
Where prescribed by the programmed protocol contained in the computer control unit, after execution of a first streaking pattern, the streaking tool 314 may be lifted until the head is clear of the culture medium's surface and another plate 310 with a fresh agar spreading surface may be presented to the inoculation and streaking station 341.
Further inoculation with the same specimen sample may then be optionally effected.
Provision is also preferentially made for sterilizing the spreading head between streaking with fresh specimens in any of various known manners.
A feature of the streaker mechanism is that, due to its sample mechanical configuration and computer control system, the streaking head spans a planar space that covers as much of the culture medium surface as is required, and is totally versatile as to the streaking patterns it may execute.
The streaking patterns chosen may conveniantly vary with and correspond to the identity of the specimen from which the culture being streaked was obtained.

The foregoing has constituted a description of specific embodiments showing how the invention may be applied and put into use. These embodiments are only exemplary. The invention in its broadest, and more specific aspects, is further described and defined in the claims which now follow.
These claims, and the language used therein, are to be understood in terms of the variants of the invention which have been described. They are not to be restricted to such variants, but are to be read as covering the full scope of the invention as is implicit within the invention and the disclosure that has been provided herein.

Claims (2)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY ARE CLAIMED AS FOLLOWS:

1. An automated overall specimen container transport, handling and inoculating system for transferring bacteria to a cultivating medium, followed by streaking of such bacteria onto such medium wherein a computer controlled specimen positioning system conveys the specimen from its original container to a deposit location on the culture medium and a computer controlled streaking tool carried by a streaking mechanism is then directed to the same deposit location based upon digitally stored data corresponding to the precise position of such deposit location, whereat the streaking tool then enters the culture medium and effects streaking.

2. An apparatus for transferring bacterial culture specimens from specimen containers identified by specimen indicia corresponding to each specimen to a culture medium comprising:
(1) carrier means to deliver the specimens to the station of a specimen extraction means;
(2) a specimen extraction means for opening the specimen containers and extracting a metered amount of specimen sample;

(3) an indicia reader for identifying the specimen indicia for the specimen and for providing a signal to a specimen streaker;
(4) transfer means for transferring the specimen sample to a streaking station having a culture medium present; and (5) streaking means for distributing the specimen sample to the culture medium wherein the streaking pattern executed by the streaking means is controlled by the signal from the indicia reader so as to correspond to the specimen sample.