Method For Taking And Transferring Bacteria Samples

Abstract

A tape dispenser, having means for supporting a nondrying adhesive tape therein, includes a depending mandrel having a flat surface of predetermined area. Tape from the roll is unrolled and pulled over the mandrel with the sticky side out. The flat surface of mandrel covered with the tape is pressed on a surface to be tested for bacteria, and the contaminated tape, over the mandrel, is then pressed onto surface of a culture medium. By using gelatin-like culture medium, it may be held upside down for transfer of bacteria from the dispenser, to prevent extraneous contamination from airborne bacteria.

Description

The present invention relates to bacteria sampling, and more particularly to a novel method and improved apparatus for gathering samples of bacteria and transferring the bacteria samples to culture media.

Heretofore, sterilized cotton swabs moistened with a sterilized liquid have been employed for taking samples of bacteria from selected surfaces, such as equipment, walls and animal surface tissue, floors, etc. The samples once taken were transferred from the surface of the media after which the samples were incubated. After predetermined periods of incubation, counts of the bacteria present in the cultures were made. These bacteria counts which represent the bacteria present in the bacteria samples were then compared to a predetermined standard, and thereby the degree of cleanliness of the selected surfaces from which the samples were taken was determined.

In using such bacteria sampling techniques wherein the bacteria counts of different samples are compared against a predetermined standard count, or against each other, it is essential that the bacteria samples be taken uniformly in order to obtain meaningful results which are truly a measure of the relative cleanliness of the selected surfaces from which the samples were taken. Consequently, with the use of cotton swabs, it has been found necessary to train technicians in the art of gathering bacteria samples from selected surfaces and transferring these samples to cultures. In an attempt to obtain uniformity, one technique taught to technicians for gathering and transferring samples has been to lightly roll a swab across a selected surface, thereby to gather the bacteria sample, and thereafter to transfer the bacteria sample to the culture by lightly rolling the swab thereacross. A disadvantage inherent with such a method of taking bacteria samples is that the uniformity of the samples taken primarily depends on the skill of the particular person gathering the samples.

Accordingly, it is an object of the present invention to provide a novel method and improved apparatus for gathering and transferring bacteria samples which obviates the disadvantages of the prior art.

It is further an object of the present invention to provide a novel method as set forth which is characterized by employing a non-drying adhesive substance for gathering and transferring bacteria samples.

It is additionally an object of the present invention to provide an improved apparatus as set forth which employs a material having an adhesive surface for gathering and transferring bacteria samples in a convenient, quick and uniform manner.

It is also an object of the present invention to provide a novel apparatus as set forth which is constructed in such a manner as to enable unskilled persons, as well as trained bacteriologists, to obtain uniform bacteria samples from selected surfaces.

In accomplishing these and other objects and advantages, there has been provided, in accordance with the present invention, a tape dispensing means including a roll of tape. The tape has a nondrying adhesive material on at least one side thereof and is dispensed so as to pass across a flat mandrel-like surface positioned on the tape dispensing means with the adhesive side out. Thereby, the tape may be positioned against the predetermined area, mandrel-like surface and bacteria samples may be taken from a selected surface by employing the mandrel to press the adhesive side of the tape against the selected surface. The bacteria sample is taken from a predetermined area of the selected surface and is transferred to a culture media such as an agar-agar culture medium by employing the mandrel to press the same adhesive surface of the tape against the surface of the culture medium. The tape may then be unrolled to position a fresh unused portion of the tape over the mandrel, and another bacteria sample may be taken immediately. Means are, also, provided on the tape dispensing means for severing portions of the tape from the tape roll. Thus, there is provided an improved apparatus for taking bacteria samples which enables unskilled personnel to take uniform bacteria samples by the novel method of using a nondrying adhesive substance to gather bacteria samples from a selected surface and transfer the sample to a culture medium for incubation.

A better understanding of the present invention may be had from the following detailed description when read in conjunction with the accompanying drawings, in which:

FIG. 1 is a pictorial representation of an apparatus for gathering bacteria samples in accordance with the present invention;

FIG. 2 is a top view of the apparatus of FIG. 1 with a roll of adhesive tape positioned therein and being dispensed therefrom;

FIG. 3 is a sectional view taken along the line 3--3 of FIG. 2 showing the tape dispensed from the roll of adhesive tape and positioned for taking and transferring a bacteria sample;

FIG. 4 is a front elevational view of the apparatus of FIG. 1;

FIG. 5 is a pictorial view of the apparatus of FIG. 1 in position below an upside down tray containing a gelled culture medium with a cover for the apparatus shown adjacent the apparatus; and

FIG. 6 is a side elevational view of a modified form of tape dispenser, according to the invention.

Referring to the FIGS. 1-4 in more detail, there is shown a tape dispensing means, indicated generally by the numeral 1, having a housing 2. The housing 2 is formed by two interlocking sections 2a and 2b which, when joined, form a flat rectangular shaped box having a shaft 3 centerally disposed therein and a slot-like opening 4 defined in one side thereof. In one form, the rectangular shape of the box defined by the housing 2 is generally square and the slot 4 is preferably located at approximately the center of one of the sides of the housing 2. Other configurations of the dispenser may be utilized to meet the requirements. For example, an essentially round housing is satisfactory for many purposes.

The tape 5 is preferably loaded in the housing 2 under sterile conditions and housing seal for protection against contamination. The roll of tape 5 is shown positioned in the dispensing means 1 in FIGS. 2 and 3. In FIG. 2, the tape 5 is shown unrolled so as to extend through the slot 4 and over a depending mandrel 6.

The mandrel 6 is mounted on the side of the housing 1 adjacent the slot 4. As shown in FIGS. 1 and 3, the mandrel 6 is mounted below the slot 3 and is shaped to provide a flat surface 7 of predetermined area extending away from the housing 2. Generally, the surface 7 is substantially parallel with the side of the housing 2 upon which the mandrel 6 is mounted. Where desired, the area may be rounded, rather than flat, to facilitate taking samples from various surfaces.

Mounted on the same side of the housing 2 as the mandrel 6 is a serrated cutting edge 8, near the upper end of the housing 2 above the slot 4. The cutting edge 8 is serrated to provide a simple and easy means for cutting used portions from the tape 5.

As shown in FIG. 2, the width of the tape 5 is slightly greater than the width of the mandrel 6. This is intentional so that the tape 5 completely covers the mandrel 6, and when bacteria samples are taken with the tape 5 the mandrel is not contaminated by the bacteria. This prevents accidental contamination of the tape from bacteria present on the mandrel 6. Further, it is noted that the tape 5 preferably has an adhesive substance only on its inner surface 5a. The roll of tape 5, therefore, is positioned on the shaft 3 in the sense so that as the tape 5 unwinds the outside surface 5b of the tape 5 passes over the surface of the mandrel 6. Thus, the adhesive surface 5a of the tape 5 faces outward away from the dispensing means 1 when positioned across the flat surface 7 of the mandrel 6. Since the surface 5a is the inner surface of the rolled tape, the adhesive surface 5a is in a sterile, non-contaminated condition as unwound from the tape roll 5.

Shown in FIG. 5 is one type of a cover 9 which may be placed over the mandrel 6, if desired, whenever the dispensing means 1 is not in use, thereby, to prevent unnecessary contamination of the mandrel 6. The dispensing means 1 is shown in FIG. 5 positioned beneath a culture tray 15. The tray 15 has a culture media 16 therein which may be, for example, a nutrient broth, such as beef broth, containing a gelatinous or gum-like substance, such as agar-agar and gelled for use. The culture medium tray 15 is divided into nine marked areas, each portion being for receiving one bacteria sample. The tray 15 is shown turned upside down in FIG. 5 so that a bacteria sample gathered on tape 5 on the mandrel 6 may be moved up into contact with the culture medium and transferred to it. The culture medium is normally clear and the tray is glass or clear plastic so the sample may be observed through the tray bottom.

In operation, a roll of adhesive tape 5 is positioned in the housing 2 of the dispensing means 1 about the shaft 3. Tape 5 is then unwound from the tape roll and pulled over the mandrel 6 and its flat surface 7 as shown in FIG. 3. The tape 5 completely covers the surface 7 and the adhesive surface 5a of the tape 5 is positioned over the mandrel 6 facing outward away from the housing 2. To take a bacteria sample from a selected surface, the dispensing means 1 and in particular, the flat surface 7 of the mandrel 6, is used to press a predetermined area of the adhesive surface 5a of the tape 5 against the selected surface. This bacteria sample is then transferred to the culture 16 in the tray 15 by pressing the tape over the mandrel end against the culture 16. In practice, the culture tray 15 is turned upside down as shown in FIG. 5, and the bacteria sample is at that time transferred to one of the divided sections of the culture 16.

After taking and transferring one bacteria sample, the tape 5 is further advanced to a portion of unexposed tape pulled over flat surface 7 of the mandrel 6. Then a second bacteria sample may be taken and transferred to a marked section of the culture 16. To take additional bacteria samples, the tape procedure is merely repeated once a bacteria sample has been transferred to a marked section of the culture 16, the culture 15 is turned agar side up and placed in an incubation chamber. The bacteria samples are then incubated and observed after predetermined periods of time, such as 24 hours, 48 hours, etc. Bacteria counts are made for each marked section of the culture 16, after the desired interval of incubation as is conventional. The bacteria counts may then be compared to predetermined standards to determine the relative cleanliness of the selected surfaces from which the bacteria samples have been taken.

The modification of FIG. 6 utilizes a generally round container 30 having a tape roll supporting shaft 32 depending from one side of the container. The container may for convenience be formed of two separable halves. A depending mandrel 34, provided with a flat, predetermined area surface 35, extends from the container, with one side of the mandrel at a tangent to periphery of the container. An elongated opening 38 provides a slot through which the tape is dispensed. A depending bar 39 extends across the top of the slot and from side to side thereof. A second depending bar 40 is spaced from the first bar and it extends across the container, both bars extending with their longitudinal axes substantially parallel to the axis of the shaft. Adjacent to the second bar, on the side opposite the first bar, is a serrated cutter 42. Tape is mounted in the container so that as it is pulled out of the slot, the adhesive side is facing the bar 39.

In using the dispenser of FIG. 6, a length of tape is pulled from the roll, and wrapped around the mandrel 34 over the surface 35. A bacteria sample is taken, transferred to a culture medium, and the used portion pulled over the two depending bars 39 and 40 so that the bacterial sample section is beyond the bar 40. The adhesive sticks to the bars and the used portion is readily cut off on the serrated cutter. The user may now grasp the tape between two bars, elevated above the container surface by two bars, and sufficient tape pulled out to wrap around the mandrel for additional samples.

It is noted that in a dispensing apparatus constructed in accordance with the present invention, the flat surface on the mandrel 6 was dimensioned to have a size of approximately 3/4 inch .times. 5/8 inch. A 3/4 inch tape has a slightly greater width than the anvil, and the exemplary dispensing apparatus constructed enabled one to conveniently take bacteria samples covering an area of 3/4 inch .times. 3/4 inch (9/16 Sq. In.) from selected surfaces. Further, since to take and transfer a bacteria sample one is required to only press the flat surface 7 of the mandrel 6 against the selected surface to be sampled, it is apparent that no special skill is required to use the apparatus of the present invention. Additionally, numerous bacteria samples may be rapidly taken with the same roll of tape by merely advancing the tape sufficiently after each sample to position an unexposed and uncontaminated portion of the tape on the mandrel surface. The exposed tape may be left intact with the tape roll until numerous bacteria tests have been taken. Thereafter, the exposed tape may be cut from the tape roll by means of the cutting edges and then discarded. For storage, the mandrel, if desired, may be covered with a cover.

Thus, there has been provided an improved apparatus for taking bacteria samples which enables even unskilled personnel to quickly and conveniently gather uniform bacteria samples. The bacteria samples are taken by the novel method of using a predetermined size of surface having an adhesive substance thereon to gather bacteria samples from a selected surface and to transfer the sample to a culture for incubation. The method is unique in sampling the same size of surface each time, which provides an accurate means of correlating bacteria counts of various surfaces.

Claims

I claim:

1. The method of gathering a bacteria sample and transferring said sample to a culture medium for incubation, comprising the steps of:

a. pressing a substantially nondrying adhesive surface against a surface from which said sample is to be taken to gather said bacteria sample from said surface; and

b. pressing said adhesive surface against said culture medium to transfer said bacteria sample thereto.

2. The method recited in claim 1 including forming said adhesive surface of a predetermined area whereby uniform bacteria samples are taken.

3. The method recited in claim 1 including placing said adhesive surface on a mandrel of a predetermined size and shape with the adhesive side directed away from said mandrel.

4. The method recited in claim 1 including providing said adhesive surface in tape form, unwinding said tape, and pulling said tape over a mandrel prior to said pressing step.