CA 02227317 1998-O1-16
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.
CA 02227317 1998-O1-16
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
CA 02227317 1998-O1-16
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
CA 02227317 1998-O1-16
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
CA 02227317 1998-O1-16
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
CA 02227317 1998-O1-16
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
CA 02227317 1998-O1-16
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
CA 02227317 1998-O1-16
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
CA 02227317 1998-O1-16
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
CA 02227317 1998-O1-16
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.
CA 02227317 1998-O1-16
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.
11
CA 02227317 1998-O1-16
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.
12
CA 02227317 1998-O1-16
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
13
CA 02227317 1998-O1-16
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
14
CA 02227317 1998-O1-16
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
CA 02227317 1998-O1-16
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 )
1
l5
CA 02227317 1998-O1-16
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
16
CA 02227317 1998-O1-16
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
17
CA 02227317 1998-O1-16
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
18
CA 02227317 1998-O1-16
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
19
CA 02227317 1998-O1-16
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.
CA 02227317 1998-O1-16
CONCL1JS I ON
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.
21
