GB1560236A

GB1560236A - Biological testing device

Info

Publication number: GB1560236A
Application number: GB2342977A
Authority: GB
Original assignee: American Home Products Corp
Current assignee: Wyeth LLC
Priority date: 1976-06-08
Filing date: 1977-06-02
Publication date: 1980-01-30
Also published as: CA1092499A; JPS52151786A; FR2354554A1; NL7706266A; DE2726010A1

Description

(54) BIOLOGICAL TESTING DEVICE (71) We, AMERICAN HOME PRODUCTS CORPORATION, a corporation organised and existing under the laws of the state of Delaware, United States of America, of 685, Third Avenue, New York 10017, New York, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to devices and methods used in biological testing of a bacterial suspension against a variety of reagents simultaneously. More particularly the invention relates to the field of test apparatus which contains a plurality of chambers for conducting different tests upon a common test specimen.

This invention also relates to such a test device and apparatus for the prevention of the release of gas, vapor, or liquid from the test device into the surrounding atmosphere during the use thereof.

In the past a variety of different methods have been employed for the identification of organisms in families of bacteria such as Neisseria and Enterobacteriaceae. Many of these methods have relied upon the different patterns of development of cultures in the presence of a variety of fermentation media. One of the most common species of Neisseria is N.

gonorrhoeae.

Until recent years the identification of N.

gonorrhoeae although accurate required a twelve to sixteen hour incubation period. It is now possible, however, through the use of a rapid fermentation process described by D. S. Kellogg and E. M. Turner, in an article entitled "Rapid Fermentation Confirmation of Neisseria Gonorrhoeae" published in Applied Microbiology, April 1973, p. 550- 552, to decrease the incubation time to about four hours. This method as in the past utilizes the different growth patterns of the organisms in a variety of fermentation media but is able to speed up the fermentation process through the use of a lightly buffered salt solution. The basic method of patterned growth identification however, is relatively the same. For example, N. gonorrhoeae will ferment glucose while being completely unreactive to maltose, fructose, sucrose, lactose and mannitol.

Table 1 which is taken from the Kellogg Turner article is a complete list of the species within the Neisseria genus, which include N. gonorrhoeae, showing their individual patterns against the six most common fermentation media used in their identification.

TABLE I Typical Growth Fermentation Reactions of Neisseria Species Organism Glucose Maltose Fructose Sucrose Lactose Mannitol N. gonorrhoeae + - - - - - N. meningitidis + + - - - - N. lactamicus + + - - + N. subflava + + - - - - N. flava + + + - - N. perflava + + + + - N. sicca + + + + - N. flavescens N. catarrhalis - - - - - - W. J.Brown in his paper published in Applied Microbiology, June 1974, p. 1027- 1030, developed an improved method of rapid fermentation of Neisseria gonorrhoeae based on the Kellogg-Turner method mentioned above. Brown by varying the volumes of buffer-salt solutions used by Kellogg and Turner in their testing procedure was able to reduce the time necessary to obtain positive results from approximately four to two hours.

Enterobacteriaceae is a class of bacteria found in animals wherein many of the species within a genus can be identified by its growth pattern in a variety of fermentation media. Table 2 lists the typical biochemical reactions of Enterobacteriaceae against the ten most common fermentation media used in their identification.

+ test result generally positive # test result more often positive - test result gengerally negative + test result more often negative d different biochemical types Acetoin (V.P) Nitrate Mannitol Dulcitol Inositol Sorbitol Rhamnose Sucrose Raffinose Malonate E. coli - + + d - # + d d Shigella - + j d -- d d Citrobacter - + + d - + + + d d Arizona t + + - - + + Salmonelia - + + d d + + - - K. pneumoniae + + + # + + + + + + E.aerogenes + + + - + + + + + + E.cloacae + + + # # + + + + + E. hafniae d + + - - - + - - # E. liquefaciens + + + ~ + + ~ + + Serratia + + + -+ + ~ + - Proteus vulgaris - + - - - - d + - P. mirabilis d + - - - - - + - P. morganii - + - - - - - d - P. rettgeri - + + - + - d d - Providencia alcalifaciens - + d - - - - d - Providencia stuartii -+ d t + d - d - - Edwardsiella + - - - - - - Although the above-mentioned methods have resolved most of the objections as to time of incubation and accuracy of results they still require a human operator to first prepare the ferementation media and place them in a series of test tubes or containers and then individually inoculate these tubes with the bacterial suspension to be tested.

This preparation process is not only time consuming, but also has the disadvantage of exposing the operator to the baceterial suspension while inoculating the tubes. In some cases such as in testing of Errterobacteriaceae there can be as many as twenty tubes to be prepared and inoculated. Thus it can be seen that the amount of handling and time required to complete the inoculation can become quite substantial. Another difficulty is that the tubes or containers must be suitable to be subjected to a water bath for accelerating the rate of reaction.

U.S. Patent No. 3,832,532 which issued on August 27, 1974, in addition to dislosing a photometric apparatus and an incubator shaker device, discloses a compartment container for testing an inoculated broth against a variety of antibiotics. This device consists of a plurality of linear arranged curvettes attached and in communication with an end reservoir. Initially the end reservoir is filled with the broth to be tested and then, through a three step physical manipulation of the entire apparatus, the inoculated broth is delivered to the plurality of curvettes and thus contacts the individual antibiotic discs located at the bottom of the curvettes.

U.S. Patent No. 3,878,377 which issued on April 8, 1975 discloses a plurality of transparent microreceptacles mounted on a thin support each of which is provided with a dosed quantity of determined coloured reagents. The product to be analysed is introduced into each receptacle in liquid form and the reaction or non-reaction is observed.

Unlike the present invention inoculation of the above-mentioned micro-receptacles must be done individually. Also these micro-receptacles cannot be sealed once the product to be analysed is introduced; thus heating in a water bath to speed up the fermentation process would be difficult.

In one aspect this invention relates to a biological testing device comprising a container and plug. The container in combination with the plug makes it possible to test a bacterial suspension with a number of different reagents simultaneously. The plug which fits within the opening of the container distributes the baceterial suspension in substantially equal amounts to tubes having different testing reagents.

Accordingly this invention provides a biological testing device comprising a tubular container open at one end and having disposed adjacent the inside periphery of the closed end portion, and opposite the open end, a plurality of tubes each having an opening facing the open end portion of the container; the tubes and the closed end portion of the container forming an open central chamber therewithin facing and substantially in alignment with the opening in the container; each of said tubes being adapted to hold at their closed ends a predetermined chemical reagent: the bottom of the central chamber being adapted to receive a sample of bacterial suspension; and a plug adapted to seal in an initial position the open end portion of the tubular container such that in use inversion of the entire apparatus enables the bacterial suspension to flow from the central chamber to the sealed open end portion below the open end portion of the tubes; the plug being further adapted to seal in a final position the central chamber from the open end of the tubes while the device remains in its inverted position such that reinversion of the device enables the bacterial suspension to flow in substantially equal amounts to the individual tubes.

Preferably the tubular container has an opening in its upper portion extending across the longitudinal axis of the tubular container, the lower portion of the tubular container being closed, and a structure forming a plurality of tubes disposed adjacent the inside periphery of the lower portion of the container; each tube having its length extending substantially parallel to the longitudinal axis of the container and having an open end portion facing the opening in the upper portion of the container and a closed end portion disposed opposite thereto.

Preferably the plug for closing the upper portion of the container has a cap portion and a neck portion narrower than the cap portion and adjacent thereto, the cap and neck portions forming a shoulder therebetween, the cap portion of the plug being adapted to fit slidingly and removably within the upper portion of the container to substantially seal the container, the plug having an initial position with respect to the container in which the cap portion of the plug is engaged with the upper portion of the container and the shoulder portion of the plug is spaced from the open end of each of the plurality of tubes, thus enabling the test suspension to pass from the central open chamber to the shoulder of the plug when the testing device is inverted; the neck portion of the plug being adapted to fit slidingly and removably within the central open chamber and to substantially seal said chamber when the plug is inserted further into the container, the plug having a final position with respect to the container in which the cap portion of the plug is further within the upper portion of the container, the neck portion of the plug engages and substantially seals the open central chamber and the shoulder portion of the plug is adjacent the open end of each of the plurality of tubes and substantially divides the test specimen in an approximately equal amount with respect to each of the tubes, the divided test specimen being confined within the individual tubes as the testing device is reinverted.

Preferably the plug is provided with a passage extending through the length of the plug from the cap portion of the neck portion for venting the interior of the central chamber of the container when the plug is inserted into the container; the size of the passage being sufficient to pass air for venting but to oppose the movement of liquid therethrough. It is preferred that the shoulder of the plug substantially closes the open end of each of the plurality of tubes, when the plug is moved to its final position with respect to the container.

Preferably the portion of each tube of the plurality of tubes adjacent the open end portion thereof and facing the central chamber has an aperture for venting the tube to the central chamber.

At least one of the container and plug can.

be provided with means for retaining the plug at each of its initial and final positions relative to the container. A preferred means comprises having first and second seating grooves in the surface of the cap portion of the plug which are adapted to fit within the upper portion of the container, the grooves being spaced apart from one another at a distance corresponding to the length of travel of the plug from its initial to its final position; the upper portion of the container having a retaining ridge positioned on the inner surface thereof to engage one of the grooves when the plug is in one of the initial and final positions, in order to retain the plug therein.

Preferably each tube of said plurality of tubes is provided with a textured surface so as to effect good adhesion of the predetermined chemical reagent to said inner surface. The microtubes can be for example individual tubes arranged in a circular fashion around the central chamber, or an integral part of the base container and arranged in a circular fashion around the central chamber. The plug can be provided with a skirt portion for containing the bacterial suspension when the device is initially inverted, thereby minimising contact of the suspension with the sides of the container and possible leakage of suspension past the plug.

In use the closed end of each tube is provided with a dehydrated chemical reagent material for testing a bacterial suspension. Prior to the use of the device, the plug is removed from the container, thus exposing the central chamber and surrounding tubes located at the bottom of the container. The bacterial suspension to be tested is then disposed in the central chamber. Thereafter the plug is partially inserted into the container and the total device is inverted. While the device remains in its inverted position, the plug is urged inwardly with respect to the container until it is fully inserted into the container. The plug may be provided with a vent passage to prevent excessive or undesirable pressure conditions within- the container when the plug is urged thereinto.At this time the entire device is re-inverted, thereby distributing substantially equal amounts of bacterial suspension to each of the tubes.

If desired, such a testing device when suitably constructed can be heated in a warm water bath to speed up testing of the bacteria against a number of reagents.

Further the testing device may be used to divide a bacterial suspension into substantially equal aliquots enabling it to be tested against a variety of reagents.

This invention also comprises a method for testing a bacterial suspension against a plurality of testing reagents, by-employing a tubular container being open at one end portion and having disposed adjacent the inside periphery of the closed end portion, disposed opposite the open end portion, a plurality of tubes each having an opening facing the open end portion of the container, the container having an open central chamber, each of said plurality of tubes being provided at their closed end opposite the opening thereof with a predetermined chemical reagent, wherein the method comprises (a) depositing a sample of bacterial suspension to be tested into the bottom of the central chamber, (b) sealing the open end portion of the tubular container, (C) inverting the entire apparatus such that the bacterial suspension flows to the sealed open end portion below the open end portion of the tubes, (d) sealing the central chamber from the open end of the tubes while the device remains in its inverted position; and (e) reinverting the device to enable the bacterial suspension to flow in substantially equal amounts to the individual tubes.

This invention further provides an assembly comprising a biological testing device as hereinbefore described and a compression compensator apparatus for preventing gas, vapour or liquid from being vented from the biological testing device.

The compensator is described and claimed in our copending U.K. Patent Appln. No.

39618/78 (Serial No. 1,560,237). The compensator comprises a chamber which is in communication with the interior of the container when the plug is in place thereon.

The chamber contains a disc therein which can move in the manner of a piston to increase the volume of the chamber and thereby receive any gas or vapor vented from the testing device during use.

The chamber of the compression compensator apparatus is adapted to cover the vent passage or aperture of the biological testing device in order to prevent gas, vapor or liquid from being vented from the testing device into the surrounding atmosphere. This apparatus helps to prevent the escape of possibly contaminated fluid from the interior of a biological testing device during its use. The chamber of the compensator contains a movable piston-like disc which enables the volume of the chamber in communication with the vent passage to be varied. Thus the portion of the chamber adjacent the vent passage is sealed from the atmosphere while the remaining portion of the chamber is adapted to be vented to the atmosphere.

Prior to the use of the compensator with the test apparatus, the disc is placed in its initial position within the chamber which is to be adjacent the vent passage. The compression compensator is then attached to the portion of the biological testing device having the vent passage. Thereafter the biological testing procedure is carried out. During the use of the testing apparatus, gas or vapor within the testing device may become contaminated by the bacterial suspension being tested. When such gas or vapor is expelled from the testing device, it is introduced into the portion of the chamber of the compression compensator between the connection to the vent passage and the disc. The introduction of such gas or vapor results in an increase of pressure within the lower chamber causing the disc to be moved along the chamber in the manner of a piston.As the disc moves, it increases the volume of the chamber into which the expelled gas or vapor can be stored. The volume of the other portion of the chamber is proportionally decreased by the movement of the disc and the excess air from the other portion is vented to the atmosphere.

Accordingly the compression compensator apparatus for preventing gas, vapour or liquid from being vented from a biological testing device into the surrounding atmosphere comprises a tubular chamber adapted to cover the vent passage or aperture of the biological testing device and a movable piston-like disc located within the chamber which enables the volume of the chamber in communication with the vent passage to be varied, whereby in use the portion of the chamber adjacent the vent passage is sealed from the atmosphere by the disc while the remaining portion of the chamber is vented to the atmosphere.

The aforementioned compensator apparatus can be used on a testing device where the plug has a vent passage extending from the interior of the container to the external surface of the plug for venting fluid from the interior of the container.

Preferably the chamber is formed by tubular structure having an opening at each of the end portions oppositely disposed along the length, and has means for mounting an end portion on the external surface of the plug; an opening of the tubular chamber being in communication with the vent passage of the plug.Preferably the disc, disposed within such a tubular chamber, has its oppositely disposed sides intersecting the length of the tubular chamber, and its periphery in a sliding and sealing engagement with the inner surface of the tubular chamber; the disc being adapted to be displaced along the length of the tubular chamber in response to fluid vented by the vent passage from an initial position adjacent the end portion of the chamber which is adapted to be mounted on the external surface of the plug by the mounting means; the displacement of the disc forming a sealed volume within the tubular chamber in which fluid vented by the open passage can be contained.

Preferably the means for mounting an end portion of the tubular chamber on the external surface of the plug for closing off the interior of the body portion of the biological testing device comprises a rim extending about the opening of the end portion of the tubular chamber which is adapted to be mounted in communication with the vent passage of the plug, the rim being adapted to frictionally engage the plug to retain and seal the tubular chamber with respect to the external surface of the plug.

Preferably the disc disposed within the tubular chamber with its periphery in a sliding and sealing engagement with the inner surface of the tubular chamber further comprises a flange extending about the periphery of the disc and away from at least one side thereof, the outer surface of the flange having a sliding fit with the inner surface of the tubular chamber for maintaining the disc in a position in which its oppositely disposed sides intersect the length of the tubular chamber when the disc is displaced along the length of the tubular chamber.

Preferably the outer surface of the flange of the disc further comprises a recess extending about the periphery of the flange, the portions of the outer surface of the flange at opposite sides of the recess being adapted to position and seal the disc with respect to the inner surface of the tubular chamber. Preferably the flange extends away from each of the opposite sides of the disc and the width of the recess in the outer surface of the flange extends away from each of the opposite sides of the disc.

Preferably the tubular chamber has an end wall at the end portion thereof opposite the end portion having an opening adapted to be mounted in communication with the vent passage in the plug, the end wall having at least one opening for venting the portion of the interior of the tubular chamber between the disc and the opening when the disc is displaced along the length of the tubular passage.

For a fuller understanding of the invention reference is made to the following description taken in connection with the accompanying drawings of a preferred embodiment in which: Fig. I is a perspective view of the biological testing showing the plug removed from the container; Fig. 2 is a plan view of the testing device; Fig. 3 is a vertical section view of the container with the plug removed and showing a bacterial suspension disposed in its lower central chamber; Fig. 4 is a vertical section view of the container with the plug inserted to its initial position; Fig. 5 is a vertical section of the container inverted while the plug is inserted to its initial position and the bacterial suspension is resting on the shoulder of the plug;; Fig. 6 is a cross-sectional view of the apparatus showing the plug fully inserted to its final position and the shoulder of the plug contacting the opening of the tubes; Fig. 7 is a cross-sectional view of the apparatus right-side up showing the plug inserted to its final position and the suspension to be tested contacting the reagent media at the bottom of the tubes; Fig. 8 is a vertical section view of an embodiment of the apparatus in which the plug is provided with a skirt portion to contain the suspension being tested; Fig. 9 is a perspective view of the apparatus showing indicia on the outer surface thereof; Fig. 10 is a fragmentary vertical section view showing the container provided with a compression compensator with the separation disc thereof in its initial position;; Fig. 11 is a vertical section view of the compression compensator mounted in its operative position; and Fig. 12 is a fragmentary vertical section view of a seal construction for the separation disc of the compression compensator.

As shown in the drawings the biological testing device of the present invention comprises essentially two parts intended to work in conjunction with each other to distribute a substantially equal amount of bacterial suspension simultaneously to a number of different reagents.

Referring now more particularly to the accompanying drawings wherein like numerals designate similar parts throughout the various views, attention is directed first to Fig. 1, wherein the biological testing apparatus 10 of the present invention comprises a hollow base container 20 herein after referred to as a container and a plug 30.

By way of example, the container and plug can each have an outside diameter less than one inch. Arranged around the inside wall of the lower portion of the container and extending vertically approximately half-way up the inner wall 21 is a plurality of tubes 22.

These tubes are open at the top and are provided with venting apertures 23. These tubes as shown in Fig. 3 are also provided at the bottom with different dehydrated reagents 24 for testing a bacterial suspension 26. As shown in Fig. 2 the arrangement of the tubes 22 around the inside wall 21 of the container, provides for the formation of a central chamber 25 at the lower half of the container 20. This central chamber is adapted to hold the bacterial suspension to be tested. These tubes can comprise a plurality of separate tubes, or may be integrally formed or molded as part of the base container.

Referring again to Fig. 1, the upper portion of the container is provided with a ridge 21a which can be molded or formed to the inside wall 21 of the container 20. The ridge is adapted to engage and seat within the groove 31 or groove 32 located on plug 30 when the plug is inserted into the container. The ridge and grooves make it possible to lock the plug in an initial position when ridge 21a is seated in groove 31 and a final position when ridge 21a is seated in groove 32. Alternatively the grooves 31 and 32 may be located on the inside wall 21 of the container 20 and the ridge 21a may be located on the plug 30.

As can be seen from Fig. 1, plug 30 is composed of an upper cap portion 30a and a lower neck portion 30b. The neck portion is adapted to fit slidingly and removably into the central chamber 25 located within the lower portion of the container 20. The upper portion of the plug 30 is adapted to fit slidingly and removably into the upper portion of the container 20. Since the cap and neck portion of the plug are of different sizes, a shoulder 33 is provided where the cap portion of the plug joins the neck portion of the plug. The shoulder 33 contacts and seals the opening of the tubes 22 when the plug is fully inserted into the container.It should be noted that the plug 30 and container 20 are designed such that when the plug is inserted into the container, the upper portion 30a of the plug forms a substantially air tight seal with the upper portion of the container 20, thus preventing the passage of liquid and air to the exterior of the apparatus.

Furthermore when the plug is fully inserted into the container, the outside surface of the lower portion 30b of the plug contacts the inside surface of the central chamber 25 located in the lower portion of the container, it also forms a substantially air tight seal between the central chamber and the rest of the container, the plug prevents the passage of liquid from the upper portion of the container to the central chamber.

Plug 30, when inserted into the container, forms a substantially air-tight seal with the container, thereby preventing escape of air from the interior of the device which results in the formation of an internal pressure within the central chamber and surrounding tubes. This can cause resistance to the insertion of the plug fully into the container.

Such resistance due to pressure can be reduced by a system of venting apertures and passages which connect the interior of the container and tubes to the outside atmosphere in the following manner.

Referring to Fig. 1, each tube 22 is provided at its open end with a venting aperture 23 which vents the interior of the tubes to the central chamber. The central chamber 25 is in turn vented to the exterior of the apparatus by means of a vent passage 34 extending vertically through the plug. This vent passage is of a size to prevent the passage of solution to the exterior of the device and yet allow the escape of air from the internal chambers of the container so that full insertion of the plug into the container is possible. By way of example, vent passage 34 may comprise a fine bore hole such as that produced by a &num;80 drill.

Although the passageway 34 greatly reduces the pressure within the central chamber and surrounding tubes, thereby allowing the plug 30 to be easily inserted, it should be understood that this passageway is optional and that the apparatus will function properly without it.

Prior to the use of this device, plug 30 is removed from the container 20, thereby exposing the interior of the central chamber 25 located at the bottom of the container as shown in Fig. 2. The bacterial suspension 26 to be tested, in liquid form is then disposed in the bottom of the central chamber 25.

Immediately thereafter the plug is partially inserted into the container until the initial seating groove 31 located on the plug 30 engages the retaining ridge 21a positioned on the inside wall 21 of the upper portion of the container as shown in Fig. 4, thereby locking the plug in its initial position. In this initial position the upper p.ortion of the container 20 is sealed by the upper portion 30a of the plug 30: however, the lower or neck portion 30b of the plug 30 has not yet contacted the inner walls of the central chamber 25 nor has the shoulder of the plug contacted and sealed the opening of the tubes 22. As can be seen from Fig. 4, when the plug is in its initial position the central chamber 25 has not yet been sealed to the space which exists between the shoulder 33 of the plug and the top of the tubes.

The entire testing device is then fully inverted as shown in Fig. 5 while the plug is still in its initial position relative to the container. This causes the bacterial suspension 24 to travel down along the cone-shaped tip of the neck portion of the plug as shown by arrows in Fig. 5 and come to rest on the shoulder 33 of the plug. The cone-shaped tip of the neck portion of the plug depicted in the preferred embodiment serves a two-fold purpose. One is to ensure that no liquid is trapped in the central chamber 25 when the plug is fully inserted into the container as would be possible if the end of plug 30 were flat. Secondly the coneshaped tip helps divert the suspension 26 away from the vent passage 34, leaving it unobstructed to vent the interior of the container of air.As mentioned above, upon inversion of the device bacterial suspension 26, has come to rest on shoulder 33. Since the suspension is in liquid form it will seek its own level and distribute itself evenly around the plug. This even distribution will play an important part in determining the subsequent division of the suspension into equal aliquots to be delivered to the tubes.

While the device is still in the inverted position the plug is urged further into its final position, so that, as shown in Fig. 6 the final seating groove 32 engages the retaining ridge 21 a on the inside wall of the upper portion of the container. In this position the neck portion 30b of the plug 30 comes into communication with the inside wall of the central chamber 25, sealing it with respect to the bacterial suspension 25 which is still resting on shoulder 33 of the plug. At the same time the top openings of the tubes 22 are brought into communication with shoulder 33 of the plug, whereupon the suspension 20 which has been resting on the shoulder is divided into equal aliquots by the upper open portion of the tubes 22. The entire device is then reinverted as shown in Fig. 7.The liquid suspension 26 which has been evenly divided by the upper open ends of the tubes 22 now descends into the tubes 22 and comes into contact with dehydrated reagents 24 located at the closed end of the tubes 22. Thereafter the bacterial suspension may or may not react with the individual reagents and thereby perform the required test procedure. During construction of the apparatus the inner surface of the closed end portions of the tubes are textured or roughened to facilitate the adhesion of the chemical test reagent to the closed end portion of the tubes.

If it is desired to speed up the test reaction, the entire apparatus may be placed in a warm water bath. As shown in Fla. 9 the apparatus is designed such that, in the closed condition, the tubes are sealed both from each other and from the exterior, thus the operator does not have to be concerned about keeping the apparatus in an upright position.

Although the container and plug of the present invention may be constructed of a variety of different materials, one should keep in mind when selecting the material to be used the type of bacterial suspension and the reagents which are to be used in conjunction with the apparatus, since any reaction between the container and its contents must be avoided.

The use of transparent plastic resin such as polystyrene is convenient for the construction of the container since it is not only chemically inert to the bacteria and reagents but also has the added advantage of being transparent and easily molded. The transparency enables the operator to clearly view at a glance the reaction or nonreaction taking place within the tubes. If the container is constructed of a nontransparent material, it should be provided with viewing windows or a transparent strip which would run around the circumference of the container, making observation of the interior of the microtubes possible. The plug can be constructed from a variety of different resilient-type materials such as polystyrene which would improve the sealing capabilities of the plug with the container.

As mentioned in the foregoing disclosure when the plug is inserted into the container it forms a number of substantially air tight seals. The quality of these seals may be increased, if desired, by a number of rubber sealing rings, which can be located on the outer circumference of the plug. The first is located on the cap portion of the plug to increase the quality of the seals between the plug and the upper portion of the container.

The second is located on the neck portion of the plug to increase the seal between the neck portion of the plug and the central chamber of the container. when the plug is in its final position. The third is located on the shoulder 33 of the plug, to increase the quality of the seal between the upper open portion of the tubes and the remainder of the container, when the plug is in its final position.

Another embodiment of the present invention is shown in Fig. 8, wherein the plug 30 is provided with a skirt portion 35 on the outer circumference of the shoulder 33.

This skirt portion forms a trough around the shoulder portion of the plug such that when the apparatus is inverted the bacterial suspension 26 will rest within the trough, thereby preventing any leakage of the suspension between the cap portion of the plug and the inner wall of the upper portion of the container 20, from occurring. This leakage will not normally occur unless the apparatus is left in the inverted position for a sustained period of time.

Fig. 8 also shows the open end portion of the microtubes 22 being provided with a relieved portion 36, at a point where the tubes meet the inside wall of the container 20. This relieved portion accept the penetration of the skirt portion 35, thereby permitting the open end portion of the tube to come into direct communication with the shoulder 33.

In Fig. 9, there is shown the application of numbers or symbols 40 to the outside of the container. These numbers or signals designate the different tubes and facilitate the identification of the different test reagents as well as the test results. The base container may also be provided with a gradient scale 41 such that the operator of the device can easily determine the volume of suspension introduced into the central chamber or the amount of suspension contained in each of the tubes.

Still another embodiment of the present invention is shown in Figs. 10 and 11 wherein the upper cap portion 30a of the plug is provided with extension cap portion 30c. The extension cap portion 30c protrudes above the outer walls of the container 20 when the plug is in its final position. This extension provides a means of attachment for a compression compensator 49.

In many instances where the operator is testing a bacterial suspension containing bacteria which are not infectious, the apparatus can be used without compensator 49 and the air from within the apparatus can be vented directly to the atmosphere.

Where the testing involves a bacterial suspension containing bacteria which are contagious, it is preferred that any air vented from the venting passage 34 of the plug 30 to be safely contained within a closed chamber. This provision is advisible since the air vented from passage 34 has been in previous contact with the bacterial suspension 26. As a result of such contact it is possible that a bacterial aerosol could be released from passageway 34 as the plug 30 is urged into its final position, as shown in Fig. 7.

In order to eliminate the possible release of a bacterial aerosol, the device of the invention can be adapted with the compression compensator apparatus 49 shown in Figs. 10 and 11. The compression compensator 49 comprises a cylindrical hollow chamber wall 50 closed at its upper end portion 50a and open at its lower end portion 50b. The lower end portion 50b is adapted to fit by friction or interference in air-tight communication with the extension cap portion 30c of plug 30. As shown in Fig.

I I the extension cap portion 30c of the plug extends beyond the upper rim of container 20 to facilitate the fitting of the compression apparatus 49 to it.

Slidingly mounted within the interior portion of chamber wall 50 is separation disc 51 having flange 51a disposed about the periphery of the lower portion of the disc.

The disc divides the chamber defined by wall 50 into an upper and lower region, 52 and 53 respectively, such that the volume thereof relative to each other is dependent upon the position of disc 51 within the chamber. The upper region 52 is provided with an opening 54 which vents the air from the upper region to the atmosphere.

Prior to the use of the compression compensator 49 in conjunction with the biological testing device 10, the separation disc 51 is brought to its lowest position within the compensator as shown in Fig. 10.

The entire compensator is then mounted on the top of plug 30 by means of a simple press fit with the outer cap portion of plug 30. In this position flange 51a bottoms on the top surface of plug 30. When separation disc 51 is in its initial or lowest position, region 53 is of a smaller volume than region 52.

Moreover, region 53 is completely sealed from the upper region 52 as well as the surrounding atmosphere while the upper region 52 is free to vent to the atmosphere through opening 54.

When the plug 30 is inserted into container 20, subsequent to the introducing of the inoculated bacterial suspension into the container 20, the air within the container 20, which has come into contact with the bacterial suspension is vented through the plug by means of vent 34. This "possibly contaminated" air is in this way introduced into region 53 the lower portion of the compression compensator 49. The introduction of the contaminated air will cause an increase in pressure within region 53 which results in disc 51 moving upwardly, (Fig. 11) thereby increasing the volume of the lower region 53. In this way it is possible for the contaminated air to be fully contained within the said lower region.As the volume of the lower region 53 is increased, the volume of the upper region 52 is proportionately decreased and the air from the upper region 52 which has not been contaminated is vented directly to the atmosphere through venting aperture 54. It can be seen that none of the contaminated air from within the container 20 can escape to the outside atmosphere, but rather is completely contained within the compression compensator 49.

The compression compensator may be constructed of a variety of different materials. The use of a plastic resin such as polystyrene is convenient not only because it is inexpensive and easily molded, but also since it can be obtained in a transparent form. This transparency enables the user to view the movement of the separation disc 51 during the use of the device, thereby providing a visual check that the air vented from chamber 53 is being contained.

As with the biological testing apparatus itself, it is necessary that the compression compensator form a number of substantially air tight seals. The quality of these seals may be increased, if desired, by the application of a number of inexpensive sealing rings.

For example, as to the seal formed between the lower end of the compensator 49 and the plug 30, a rubber gasket or washer may be located on the upper periphery of the cap portion 30c of the plug, thereby increasing the quality of the seal between the plug and the compensator. Also the seal formed between the separation disc 51 and the inner walls of chamber 53 may be improved by fitting a rubber O-ring around the outer circumference of the disc 51. Thus the O-ring will be in constant frictional engagement with both the separation disc and the inner wall of the compensator. It should be noted, however, that this seal should not be so tight as to prevent the free movement of the disc 51 along the compensator chamber wall 50.

An alternate construction for increasing the quality of seal between the separation disc 51 and the inner wall 50 of the compensator 49 is shown in Fig. 12. The separation disc 55 formed of flexible material such as resin material is provided with an outer cylindrical rim or flange 55a.

This outer rim 55a is provided with upper and lower annular lips 55b and 55c, respectively, which contact the inner wall of the compensator. These lips form substantially two independent seals. As a result any contaminated air which, after having been introduced into the lower region 53 manages to leak past the first seal formed between the lower lip 55c and the inner wall of the compensator, will be blocked by the second seal formed between the upper lip 55b and the inner wall of the compensator. In this way leakage is prevented from entering the upper region 52 and ultimately being vented to the atmosphere.

WHAT WE CLAIM IS: 1. A biological testing device comprising a tubular container open at one end and having disposed adjacent the inside periphery of the closed end portion, and opposite the open end, a plurality of tubes each having an opening facing the open end portion of the container; the tubes and the closed end portion of the container forming an open central chamber therewithin facing and substantially in alignment with the opening in the container; each of said tubes being adapted to hold at their closed ends a predetermined chemical reagent; the bottom of the central chamber being adapted to receive a sample of bacterial suspension; and a plug adapted to seal in an initial position the open end portion of the tubular container such that in use inversion of the entire apparatus enables the bacterial suspension to flow to the sealed open end portion below the open end portion of the tubes; the plug being further adapted to seal in a final position the central chamber from the open end of the tubes while the device remains in its inverted position such that reinversion of the device enables the bacterial suspension to flow in substantially equal amounts to the individual tubes.

2. A device as claimed in Claim 1 wherein the tubular container has an opening in its upper portion extending across the longitudinal axis of the tubular container, the lower portion of the tubular container being closed, and a structure forming a plurality of tubes disposed adjacent the inside periphery of the lower portion of the container; each tube having its length extending substantially parallel to the longitudinal axis of the container and having an open end portion facing the opening in the upper portion of the container and a closed end portion disposed opposite thereto.

3. A device as claimed in Claim 2 wherein the portion of each tube of the plurality of tubes adjacent the open end portion thereof faces the central chamber and has an aperture for venting the tube to the central chamber.

4. A degree as claimed in any one of Claims 1 to 3 wherein the plug has a vent passage for venting the interior of the container when the plug is inserted into the container.

5. A device as claimed in any one of Claims 1 to 3 wherein the plug for closing the upper portion of the container has a cap portion and a neck portion narrower than the cap portion and adjacent thereto, the cap and neck portions forming a shoulder therebetween, the cap portion of the plug being adapted to fit slidingly and removably within the upper portion of the container to substantially seal the container, the plug having an initial position with respect to the container in which the cap portion of the plug is engaged with the upper portion of the container and the shoulder portion of the plug is spaced from the open end of each of the plurality of tubes, thus enabling the test suspension to pass from the central open chamber to the shoulder of the plug when the testing device is inverted; the neck portion of the plug being adapted to fit slidingly and removably within the central open chamber and to substantially seal said chamber when the plug is inserted further into the container, the plug having a final position with respect to the container in which the cap portion of the plug is further within the upper portion of the container, the neck portion of the plug engages and substantially seals the open central chamber and the shoulder portion of the plug is adjacent the open end of each of the plurality of tubes and substantially divides the test specimen in an approximately equal amount with respect to each of the tubes, the divided test specimen being confined within the individual tubes as the testing device is reinverted.

6. A device as claimed in Claim 5 wherein the plug is provided with a passage extending through the length of the plug from the cap portion to the neck portion for venting the interior of the central chamber of the container when the plug is inserted into the container; the size of the passage being sufficient to pass air for venting but to oppose the movement of liquid therethrough.

7. A biological testing device comprising: a tubular container having an opening in its upper portion extending across the longitudinal axis of the tubular container, the lower portion of the tubular container being closed, structure forming a plurality of tubes disposed adjacent the inside periphery of the lower portion of the container, each tube having its length extending substantially parallel to the longitudinal axis of the container and having an open end portion facing the opening in the upper portion of the container and a closed end portion disposed opposite thereto, the tubes and the closed end portion of the container forming a central

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. result any contaminated air which, after having been introduced into the lower region 53 manages to leak past the first seal formed between the lower lip 55c and the inner wall of the compensator, will be blocked by the second seal formed between the upper lip 55b and the inner wall of the compensator. In this way leakage is prevented from entering the upper region 52 and ultimately being vented to the atmosphere. WHAT WE CLAIM IS:

1. A biological testing device comprising a tubular container open at one end and having disposed adjacent the inside periphery of the closed end portion, and opposite the open end, a plurality of tubes each having an opening facing the open end portion of the container; the tubes and the closed end portion of the container forming an open central chamber therewithin facing and substantially in alignment with the opening in the container; each of said tubes being adapted to hold at their closed ends a predetermined chemical reagent; the bottom of the central chamber being adapted to receive a sample of bacterial suspension; and a plug adapted to seal in an initial position the open end portion of the tubular container such that in use inversion of the entire apparatus enables the bacterial suspension to flow to the sealed open end portion below the open end portion of the tubes; the plug being further adapted to seal in a final position the central chamber from the open end of the tubes while the device remains in its inverted position such that reinversion of the device enables the bacterial suspension to flow in substantially equal amounts to the individual tubes.

open chamber therewithin facing and substantially in alignment with the opening in the container, the chamber being adapted to hold a biological test suspension; and a plug for closing the upper portion of the container, the plug having a cap portion and a neck portion narrower than the cap portion and adjacent thereto. the cap and neck portions forming a shoulder therebetween, the cap portion of the plug being adapted to fit slidingly and removably within the upper portion of the container to substantially seal the container, the plug having an initial position with respect to the container in which the cap portion of the plug is engaged with the upper portion of the container and the shoulder portion of the plug is spaced from the open end of each of the plurality of tubes, the plug in the initial position thereof enabling the test suspension to pass from the central open chamber to the shoulder of the plug when the testing device is inverted, the neck portion of the plug being adapted to fit slidingly and removably within the central open chamber and to substantially seal said chamber when the plug is fully inserted into the container, the plug having a final position with respect to the container in which the cap portion of the plug is further within the upper portion of the container, the neck portion of the plug engages and substantially seals the open central chamber and the shoulder portion of the plug is adjacent the open end of each of the plurality of tubes and substantially divides the test specimen in an approximately equal amount with respect to each of the tubes, the divided test specimen being confined within the individual tubes as the testing device is reinverted.

8. The device of Claim 7 wherein said plug is provided with a passage extending through the length of the plug from the cap portion of the neck portion thereof, the passage venting the interior of the central chamber of the container when the plug is inserted into the container, the size of the passage being sufficient to pass air for venting but to oppose the movement of liquid therethrough.

9. The device of any one of Claims 5 to 8 wherein the end of the neck portion opposite the shoulder portion of the plug is tapered.

10. The device of any one of Claims 5 to 9 wherein the shoulder of the plug is adjacent and substantially closes the open end of each of the plurality of tubes, when the plug is moved to its final position with respect to the container.

I I. A device as claimed in any one of Claims I to 10 wherein each tube of said plurality of tubes is provided at the closed end thereof with a predetermined chemical reagent material.

12. A device as claimed in any one of Claims I to 13 wherein the portion of each tube of the plurality of tubes adjacent the open end portion thereof and facing the central chamber has an aperture for venting the tube to the central chamber.

13. A device as claimed in any one of Claims 1 to 14 wherein at least one of the container and plug are provided with means for retaining the plug at each of its initial and final positions relative to the container.

14. A device as claimed in Claim 13 in which the means for retaining the plug at each of its initial and final positions comprises: A cap portion of the plug having first and second seating grooves in the surface thereof which is adapted to fit within the upper portion of the container, the grooves being spaced apart from one another at a distance corresponding to the length of travel of the plug from its initial to its final position; the upper portion of the container having a retaining ridge positioned on the inner surface thereof to engage one of grooves when the plug is in one of the initial and final positions to retain the plug therein.

15. A device as claimed in any one of Claims 1 to 14 wherein the container and plug are substantially cylindrical in shape.

16. A device as claimed in any one of Claims I to 15 wherein the container is formed of a transparent resin material.

17. A device as claimed in any one of Claims 1 to 16 wherein the plug is constructed of a resilient material.

18. A device as claimed in any one of Claims 1 to 17 wherein the container is provided with a means for identifying each of the plurality of tubes.

19. A device as claimed in any one of Claims I to 18 wherein inner surface of the closed end portion of each tube of said plurality of tubes is provided with a textured surface so as to effect good adhesion of the predetermined chemical reagent to said inner surface.

20. A biological testing device comprising: a transparent cylindrical container having an opening in its upper portion extending across the longitudinal axis of the container, the lower portion of the container being closed, structure forming a plurality of tubes disposed adjacent the inside periphery of the lower portion of the container, each tube having its length extending substantially parallel to the longitudinal axis of the container and having an open end portion facing the opening in the upper portion of the container and a closed end portion disposed opposite thereto, the tubes and the closed end portion of the container forming a central open chamber therewithin facing and substantially in alignment with the opening in the container, the chamber being adapted to hold a biological test suspension, a portion of each tube of the plurality of tubes adjacent the open end portion thereof and facing the central chamber has an aperture for venting the tube to the central chamber, said tubes also being provided at the closed end thereof with a predetermined chemical reagent material: and a plug for closing the upper portion of the container, the plug having a cap portion and a neck portion narrower than the cap portion and adjacent thereto, the cap and neck portions forming a shoulder therebetween, the cap portion of the plug being adapted to fit slidingly and removably within the upper portion of the container to substantially seal the container, the cap portion of the plug having a first and second seating grooves in the surface thereof adapted to engage a retaining ridge positioned in the inner surface of the upper portion of the container for holding the plug at an initial and final position with respect to the container, wherein the initial position the cap portion of the plug is engaged with the upper portion of the container and the shoulder portion of the plug is spaced from the open end of each of the plurality of tubes, thus enabling the test suspension to pass from the central open chamber to the shoulder of the plug when the testing device is inverted, the neck portion of the plug being adapted to fit slidingly and removably within the central open chamber to substantially seal said chamber when the plug is fully inserted into the container, the end of the neck portion of the plug opposite the shoulder portion of the plug being tapered, wherein in the final position the cap portion of the plug is further within the upper portion of the container, the neck portion of the plug is within the central chamber and the shoulder portion of the plug is adjacent the open end of each of the plurality of tubes dividing the test specimen substantially into equal amounts with respect to each of the tubes, the divided test specimen being confined within- the individual tubes as the testing device is reinverted, the plug also being provided with a passage extending through the length of the plug from the cap portion to the neck portion thereof, the passage venting the interior of the central chamber of the container when the plug is inserted into the container.

21. A device as claimed in Claim 20 wherein the passage extending through the length of the plug is of a size sufficient to pass air for venting but to oppose the movement of liquid therethrough.

22. A device as claimed in Claim 20 or 21 wherein the container is constructed of resin material.

23. A device as claimed in any one of Claims 20 to 22 wherein the plug is constructed of a resilient material.

24. A device as claimed in any one of Claims 20 to 23 wherein the microtubes are individual tubes arranged in a circular fashion around the central chamber.

25. A device as claimed in any one of Claims 20 to 24 wherein the microtubes are an integral part of the base container and are arranged in a circular fashion around the central chamber.

26. A device as claimed in any one of Claims 1 to 25 wherein the plug is provided with a skirt portion adapted to contain the bacterial suspension when the device is initially inverted.

27, A method for testing a bacterial suspension against a plurality of testing reagents, by employing a tubular container being open at one end portion and having disposed adjacent the inside periphery of the closed end portion, disposed opposite the open end portion, a plurality of tubes each having an opening facing the open end portion of the container the container having an open central chamber, each of said plurality of tubes being provided at their closed end opposite the opening thereof with a predetermined chemical reagent, wherein the method comprises (a) depositing a sample of bacterial suspension to be tested into the bottom of the central chamber, (b) sealing the open end portion of the tubular container, (c) inverting the entire apparatus such that the bacterial suspension flows to the sealed open end portion below the open end portion of the tubes, (d) sealing the central chamber from the open end of the tubes while the device remains in its inverted position; and (e) reinverting the device to enable the bacterial suspension to flow in substantially equal amounts to the individual tubes.

28. A method as claimed in Claim 27 and further comprising observing the reaction and the non-reaction of the bacterial suspension with the predetermined chemical reagent located at the closed end portion of each of the tubes.

29. A method as claimed in Claim 27 or Claim 28 wherein when sealing the central chamber the open end portion of the tubes are moved into the bacterial suspension to divide the bacterial suspension between the tubes.

30. A method claimed in any one of Claims 27 to 29 wherein the open end portion of the tubes are moved to the bottom of the bacterial suspension.

31. A device as claimed in Claim 1 substantially as hereinbefore described with reference to and as illustrated in any one of Figures 1 to 9.

32. A method as claimed in Claim 21 substantially as hereinbefore described.

33. An assembly comprising a device as claimed in any one of Claims 1 to 26 and 31 and a compression compensator apparatus for preventing gas, vapour or liquid from being vented from the biological testing device into the surrounding atmosphere: the compression compensator apparatus comprising a chamber adapted to cover a vent passage or aperture of the biological testing device and a movable piston-like disc located within the chamber which enables the volume of the chamber in communication with the vent passage to be varied, whereby in use the portion of the chamber adjacent the vent passage is sealed from the atmosphere by the disc while the remaining portion of the chamber is vented to the atmosphere.

34. An assembly as claimed in Claim 33 wherein the biological testing device has a plug having a vent passage extending from the interior of the container to the external surface of the plug for venting fluid from the interior of the container, and the compression compensator apparatus comprises: structure forming a tubular chamber having an opening at each of the end portions oppositely disposed along the length of the tubular chamber; means for mounting an end portion of the tubular chamber on the external surface of the plug with an opening of the tubular chamber in communication with the vent passage of the plug;; a disc disposed within the tubular chamber and having its oppositely disposed sides intersecting the length of the tubular chamber, the disc having its periphery in a sliding and sealing engagement with the inner surface of the tubular chamber the disc being adapted to be displaced along the length of the tubular chamber in response to fluid vented from the vent passage from an initial position adjacent the end portion thereof adapted to be mounted on the external surface of the closing member by the mounting means, the displacement of the disc forming a sealed volume within the tubular chamber in which fluid vented by the open passage can be contained.

35. An assembly in accordance with Claim 34 in which the structure forming a tubular chamber comprises structure forming a substantially cylindrical chamber and in which the disc comprises a substantially circular disc.

36. An assembly in accordance with Claim 34 or Claim 35 in which the means for mounting an end portion of the tubular chamber on the external surface of the plug comprises a rim extending about the opening of the end portion of the tubular chamber which is adapted to be mounted in communication with the vent passage of the plug, the rim being adapted to frictionally engage the closing member to retain and seal the tubular chamber with respect to the external surface of the plug.

37. An assembly in accordance with Claim 33 or Claim 34 in which the plug is substantially cylindrical in form with the vent passage therein extending along the length of the cylindrical form, in which the structure forming a tubular chamber comprises a substantially cylindrical chamber and in which the means for mounting an end portion of the tubular chamber to the external surface of the plug comprises a substantially cylindrical rim extending about the opening of the end portion of the substantially cylindrical tubular chamber which is adapted to be mounted in communication with the vent passage of the plug, the cylindrical rim being adapted to be engaged in a sealing relationship with the substantially cylindrical plug to retain and seal the cylindrical tubular chamber with respect to the external surface of the plug.

38. An assembly in accordance with any one of Claims 34 to 37 in which the disc disposed within the tubular chamber with its periphery in a sliding and sealing engagement with the inner surface of the tubular chamber further comprises a flange extending about the periphery of the disc and away from at least one side thereof, the outer surface of the flange having a sliding fit with the inner surface of the tubular chamber for maintaining the disc in a position in which its oppositely disposed sides intersect the length of the tubular chamber when the disc is displaced along the length of the tubular chamber.

39. An assembly in accordance with Claim 38 in which the outer surface of the flange of the disc having a sliding fit with the inner surface of the tubular chamber further comprises a recess extending about the periphery of the flange, the portions of the outer surface of the flange at opposite sides of the recess being adapted to position and seal the disc with respect to the inner surface of the tubular chamber.

40. An assembly in accordance with Claim 37 in which the flange extends away from each of the opposite sides of the disc and in which the width of the recess in the outer surface of the flange extends away from each of the opposite sides of the disc.

41. An assembly in accordance with any one of Claims 34 to 40 in which the structure forming a tubular chamber has an end wall at the end portion thereof opposite the end portion having an opening adapted to be mounted in communication with the vent passage in the plug, the end wall having at least one opening for venting the portion of the interior of the tubular chamber between the disc and the opening when the disc is displaced along the length of the tubular passage.

42. An assembly as claimed in Claim 33 substantially as hereinbefore described with reference to and as illustrated in any one of Figures 10, 11 and 12.