WO2000018879A1 - Petri dish enabling microorganisms to be cultured in more than two different kinds of media by single inoculation - Google Patents

Abstract

A Petri dish (20) has a brim (21) and at least one partition (22) dividing an inside space of the dish (20), into at least two sections and having a height lower than that of the brim (21). An inoculating method using the Petri dish is to first charge the sections with an appropriate amount of medium respectively, thereby enabling a portion of each of the media contacting the partition to have a same height as that of the partition after solidification of the medium. Then, a streak is carried out on the media across the partition in order to inoculate a sample on the media at the same time.

Description

PETRI DISH ENABLING MICROORGANISMS TO BE CULTURED IN MORE THAN TWO DIFFERENT KINDS OF MEDIA BY SINGLE

INOCULATION

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a Petri dish and an inoculating method using the same; and, more particularly, to a Petri dish capable of accommodating a multiple kinds of media and a method for inoculating the multiple kinds of media therein concurrently.

BACKGROUND ART

The study of microorganisms, such as yeast, bacteria, fungi, viruses, and the like, often requires the growth of the same on a solid medium. One method for growing microorganisms on solid media is to use a Petri dish filled with a solidified agar. There is shown m Figs. 1A and IB one of the prior art Petri dishes 10 which is divided into two sections 13a and 13b by a partition 12. The partition 12 has a same height as that of a brim 11. In order to culture samples on the sections 13a and 13b, media such as agar are first charged into the sections 13a and 13b, respectively.

For example, let's suppose that urinary sample is selected as a specimen to be cultured m order to obtain information about bacteria within the urine. For examination of growth of the bacteria, e.g., blood agar 14a and Macconkey agar 14b are prepared and charged m the sections 13a and 13b, respectively. Heights of the media are normally kept at 3 mm, which are lower than that of the brim 11. Then, the media are solidified. As shown m Fig. 2, the urinary sample is inoculated on the media 14a and 14b using a platinum loop 5. Such an inoculation is first carried out on the blood agar 14a and then the Macconkey agar 14b, or vice versa. Next, the Petri dish 10 is maintained at 35°C within an incubator (not shown), e.g., for a day and then removed from the incubator, to allow an operator to observe the growth of a bacterial colony.

For example, if the growth of the colony is found on only the blood agar 14a, the bacteria are classified as Gram-negative bacteria; and if the growth is found on both the blood agar 14a and the Macconkey agar 14b, they are classified as Gram-positive microorganisms. Next, the bacteria are then identified.

The prior art Petri dish and the inoculation method described above, however, have a shortcoming in that the inoculation must be performed the identical number of times as the number of media prepared. That is, although only two media are shown as examples in the above description, if the test is performed on five different media or more, the inoculation must be performed at least five times.

DISCLOSURE OF THE INVENTION

It is, therefore, a primary object of the invention to provide a Petri dish capable of accommodating a multiple kinds of media and a method for inoculating the multiple kinds of media therein concurrently . The above and other objects of the invention are accomplished by providing a Petri dish provided with a brim and at least one partition partitioning an inside space of the brim into at least two sections and having a height lower than that of the brim. In accordance with one feature of the present invention, an inoculating method using the Petri dish is provided. The inoculating method is to first charge onto the section of the inside space an amount of medium enabling surfaces of the media to be substantially flushed with an end of the partition after solidification of the medium. Then, a streak is carried out on the media across the partition m order to inoculate a sample on the media at the same time.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and features of the instant invention will become apparent from the following description of preferred embodiments taken m conjunction with the accompanying drawings, in which: Figs. 1A and IB illustrate a perspective view and a sectional view of a prior art Petri dish, respectively;

Fig. 2 depicts a top planar view of showing an inoculation of a urinary sample on the Petri dish m Fig. 1A;

Figs. 3A and 3B give a perspective view and a sectional view of a first embodiment of the inventive Petri dish, respectively; Figs. 3C and 3D show sectional views of a second and a third embodiment of the present invention, respectively;

Fig. 3E presents a sectional view of the solidification of media m the first embodiment; Figs. 4A and 4B represent top planar views showing inoculations of a urinary sample on the inventive Petri dish m Fig. 3A, respectively;

Fig. 5 offers presents a top planar view showing an inoculation of a general sample on the inventive Petri dish m Fig. 3A; Fig. 6 discloses a perspective view of a lid for use with the inventive Petri dish;

Fig. 7 sets forth a perspective view of a modification of the lid m Fig. 6; and Fig. 8 is a sectional view of the lid m Fig. 6 when it is engaged with the inventive Petri dish.

MODES OF CARRYING OUT THE INVENTION

A Petri dish and an inoculating method using the dish, m accordance with the present invention, are now described with reference to Figs. 3A and 5. As shown, the inventive Petri dish 20 includes a partition 22 having its height lower than that of a brim 21. Although one partition 22 is shown, the Petri dish can be divided into a plurality of sections by a multiple number of the partition 22 according to the examination to be performed. It is preferable that the height of the brim 21 be substantially about 10 mm; and the height of the partition 22 be identical to or lower than 4 mm.

As shown m Figs. 3A and 3B, an upper margin of the partition 22 is flat and is rectangular m shape m the first embodiment of the present invention. There are shown m Figs. 3C and 3D a second and a third embodiments 30 and 40 of the inventive Petri dish, respectively. In the second embodiment 30, an upper margin of a partition 32 is inclined from one side thereof to the opposing side as shown m Fig. 3C. In the third embodiment 40, an upper margin of a partition 42 has a rounded shape. It should be understood that the top of the partition 22 can also be U-shaped or V-shaped depending on the need.

The inoculation method using the inventive Petri dish is described with reference to Figs. 3A through 5. Description is made with respect to an examination of an urinary sample.

First, a blood agar and a Macconkey agar are prepared. These are charged into a first section 23a and a second section 23b, respectively, as shown m Fig. 3A until the agars 24a and 24b have a slight convex shape at the top thereof, illustrated m Fig. 3B, respectively. That is, a middle portion of the medium 24a or 24b has a height taller than that of verge of the medium or a substantial height of the partition 22. For example, the height of the middle portion of each of the media is about 3 mm, when the height of the partition 22 being about 2.5 mm. This can be realized by the surface tension of the medium 24a or 24b.

During the charging process, the media 24a and 24b m the first embodiment do not come m contact with each other, being separated by the partition 22. However, the media 34a and 34b m the second embodiment come m contact with an apex of the partition 32. That is, the partition 32 is almost submerged under the media 34a and 34b. The media 44a and 44b also come m contact with an apex of the partition 42 m the third embodiment shown m Fig. 3D. The second and the third embodiments provide better inoculation efficiency which will be described later, since the media 34a, 34b, 44a and 44b continuously extend. In every embodiments, a portion of the medium 24a, 24b, 34a, 34b, 44a or 44b contacting with the partition 22, 32 or 42 has a same height as that of the partition 22, 32 or 42.

Then, the medium 24a or 24b is solidified at a room temperature. After the solidification, the medium 24a or 24b is shrunk by a predetermined rate. It is most preferable that surfaces of the media 24a and 24b be flushed with the upper margin of the partition, as shown m Fig. 3E. An exact amount of the medium for forming this shape can be determined experimentally.

Next, the urinary sample is inoculated on the media 24a and 24b concurrently. That is, a platinum loop 5 is first stained with the urine.

Then, as shown m Fig. 4A, a streak is made on the media 24a and 24b across the partition 22 using the platinum loop 5, inoculating the urinary sample on the media 24a and 24b. During this process, since the media 24a and 24b and the partition 22 are flushed with one another, the streaking can be freely performed without hindrance Then, further streaking may be performed after the Petri dish 20 has been rotated by an angle of 90°, as shown in Fig. 4B. A general sample other than the urinary sample may be normally streaked on the media 24a and 24b m such a manner as shown m Fig. 5.

First, a first streak is made on both media 24a and 24b using the platinum loop 5, leaving a first partial sample on a first region of an upper portion of the media 24a and 24, as indicated with a reference numeral 101. Then, a part of the sample is moved to a second region separated from the first region by dragging down the platinum loop 5, as indicated with a reference numeral 102. Then, a second streak 103 is made to leave a second partial sample on the second region. Then, similarly, a part of the second partial sample is moved to a third region separated from the second region, as indicated with a reference numeral 104. Then, a third streak 105 is made to leave a third partial sample on the third region. Finally, a fourth partial sample is made by dragging down the platinum loop 5, as indicated with a reference numeral 106, and then a fourth streak 107. In this embodiment, since a streak is made on a region with the sample from the previous region, the concentration of the microorganism m each region is progressively lowered, eventually allowing each microorganism to proliferate separately m the media. A description on a lid for use with the inventive

Petri dish is now made with reference to Figs. 6 to 8. As shown m Fig. 6, the inventive lid 60 has two brims, i.e., an outer brim 62 and an inner brim 61. Height of the inner brim 61 must be low enough to prevent it from contacting the medium 24a m the Petri dish 20, when the lid 60 is engaged with the Petri dish 20, as shown m Fig. 8. The medium 64 such as agar can be accommodated m an inside space of the inner brim 61. Accordingly, a larger space for accommodating the medium can be obtained by using the inventive Petri

As shown m Fig. 7, a partition 73 may be formed on the lid 60 to allow the lid 60 to accommodate thereon a multiple kinds of media 64. Although the invention has been shown and described with respect to the preferred embodiments, it will be understood by those skilled m the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined m the following claims.

Claims

What is claimed is:

1. A Petri dish having a brim, the dish comprising: at least one partition dividing an inside space of the dish into at least two sections and having a height lower than that of the brim.

2. The Petri dish of claim 1, wherein an upper margin of the partition is rectangular.

10

3. The Petri dish of claim 1, wherein an upper margin of the partition is inclined from one side to an opposing side.

15 4. The Petri dish of claim 1, wherein an upper margin of the partition has a rounded shape.

5. The Petri dish of claim 1, wherein an upper margin of the partition is U-shaped.

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6. The Petri dish of claim 1, wherein an upper margin of the partition is V-shaped.

7. The Petri dish of claim 1, wherein the height of 25 the partition is identical to or lower than 4 mm.

8. The Petri dish of claim 1, further comprising: a lid having an outer brim and an inner brim, a height of the inner brim being lower enough to prevent it from

30 contacting a medium m the Petri dish, when the lid is engaged with the Petri dish.

9. The Petri dish of claim 8, wherein the lid further comprises a partition dividing an inside space of the

35 inner brim.

10. An inoculating method using the Petri dish of one of the claims 1 through 9, the method comprising the steps of :

(a) charging the sections with an appropriate amount of medium respectively, thereby enabling a portion of each of the media contacting the partition to have a same height as that of the partition after solidification of the medium; and

(b) performing a streaking on the media across the partition in order to inoculate a sample on the media concurrently .

11. An inoculating method using the Petri dish of one of the claims 1 through 9, the method comprising the steps of :

(a) charging the sections with an appropriate amount of medium respectively, thereby enabling surfaces of the media to be substantially flushed with an upper margin of the partition after solidification of the medium; and

(b) performing a streaking on the media across the partition in order to inoculate a sample on the media concurrently .