JP2002051766A - Medium for detecting microorganisms - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To further improve the growth promoting performance of a conventional yeast extract, and because the color of the culture medium is light, not only is it easy to determine the number of bacteria and the growth of the bacteria, but also the appearance color is apparent. Another object of the present invention is to provide a medium containing a yeast extract, which is good and economical. A medium for detecting microorganisms, comprising a Torula yeast extract as an active ingredient.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a culture medium for detecting microorganisms, and more particularly to a culture medium for detecting microorganisms containing a Torula yeast extract as an active ingredient.

[0002]

2. Description of the Related Art In a microorganism test at a hospital or the like, in order to detect a pathogenic bacterium causing an infectious disease, it is necessary to carry out separation culture or growth culture of a microorganism from a test material. In particular, at present, the pathology of infectious diseases is complicated and diversified, and it is becoming difficult to estimate pathogenic bacteria from clinical findings. Therefore, rapid and accurate detection results by microbial tests have become even more important.

[0003] When a pathogen is identified in this microbial test, a specimen is generally applied to an agar plate medium and separated and cultured. Depending on the culture medium used, differences occur in the shape and color of the colony in which the target bacterium has grown, and in the color change of the culture medium around the colony. Using this, the target bacterium is screened from miscellaneously developed colonies, and the process is shifted to biochemical property inspection and the like.

[0004] As a nitrogen source in a medium for culturing microorganisms, peptone prepared by hydrolyzing proteins such as milk casein, gelatin and soybean protein with enzymes such as trypsin, pepsin and papain has been used. However, even when peptone is used as a nitrogen source, there is a case where a microorganism having high auxotrophy does not grow sufficiently (Japanese Patent Application Laid-Open No. Hei 7-265066).

[0005] Therefore, as a nitrogen source, a yeast extract rich in a substance for promoting the growth of microorganisms is used. As yeast extracts, beer yeast extract and baker's yeast extract are known. Incidentally, the brewer's yeast extract is obtained by extracting excess yeast after beer fermentation, and the baker's yeast is obtained by extracting saccharomyces yeast cultured by molasses fermentation as a raw material.

[0006]

However, even when these yeast extracts are used, the growth promotion performance of microorganisms is certainly improved, but when the sample is small, it is difficult to judge positive or negative. Therefore, the appearance of a further improved medium has been strongly desired. Therefore, the present invention has been made in view of such conventional problems, and further enhances the growth promoting performance of the conventional yeast extract, the color of the solution is lighter than the conventional product, and the appearance color An object of the present invention is to provide a culture medium containing a yeast extract which is good in appearance and is inexpensive and economical.

[0007]

Means for Solving the Problems As a result of the present inventors diligently searching for a new yeast extract that replaces the conventional yeast extract, a torula yeast extract obtained by culturing Candida yeast as a molasses raw material and extracting the same was obtained as described above. Have been found, and the present invention has been completed.

[0008] The above object of the present invention has been achieved by a microorganism detection medium containing Torula yeast extract as an active ingredient. Hereinafter, the present invention will be described in more detail.

The torula yeast extract used in the present invention is obtained by culturing a molasses raw material from yeast of the genus Gandida and extracting it. This yeast extract has 5′-inosinic acid and 5 ′ as compared with conventionally used beer yeast extract and baker's yeast extract.
-It is known for its high content of guanylic acid and oligonucleotides.

In the present invention, the content of the yeast extract is 0.001 to 0.01 g / m 2 based on the total amount of the medium.
1, preferably in the range of 0.005 to 0.01 g / ml. When the content of the torula yeast extract is less than 0.001 g / ml, the ability to promote the growth of microorganisms cannot be improved. Conversely, when the content exceeds 0.01 g / ml, it becomes expensive and inferior in economy. .

The medium for detecting microorganisms of the present invention may be in any form of liquid, semi-fluid, or solid. However, from the viewpoint of easy detection, a solid medium is preferable, and more preferably, a plate solid medium. is there. Examples of the solidifying agent for the solid medium include those commonly used such as agar, carrageenan, and agarose. As the medium that can be used in the present invention,
As long as the microorganism can grow, it can be appropriately selected from known media. Specific examples of such a medium include:
Examples include a heart infusion medium, a tryptic soy medium, a mannitol salt medium, and a stapilococcus medium.

The medium composition of the present invention contains substantially Torula yeast extract, peptone, glucose, agar and purified water. The torla yeast extract, peptone, and glucose can be used in the proportions conventionally used, but usually 1.0 to 10.0 g, preferably 2.0 to 6 g of torula yeast extract per 1000 ml of purified water. .0
g, peptone 2.0-20.0 g, preferably 5.0-2.0.
15 g, glucose 0.5 to 30 g, preferably 1 to 20
g.

The solid agent (eg, agar) can be arbitrarily set depending on the desired hardness (solid, semi-fluid) of the medium to be used. The medium of the present invention is prepared by dissolving these components and adding a normal acid or base as needed to adjust the pH to 5.5.
By adjusting the ratio to the range of ~ 9.0, the detection rate of microorganisms can be further improved.

When the culture medium for detecting microorganisms of the present invention is used as a solid medium, for example, an appropriate amount of a test sample for confirming the presence of staphylococci is prepared by adding an appropriate amount of a test medium prepared in advance for the culture medium for detecting microorganisms of the present invention. Sampling is performed on a solid medium, cultured under appropriate conditions, and the presence or absence of the generated staphylococcal colonies is confirmed for the presence of staphylococci.

Although not particularly required for the present invention, pH
By using the indicator, it is possible to clearly determine whether the reaction is positive or negative even if the test sample is small. Such pH indicators are not particularly limited, and include bromthymol blue, phenol red, bromcresol purple, cresol red, and bromphenol red, with bromthymol blue being preferred.

[0016]

EFFECTS OF THE INVENTION The microorganism detection medium of the present invention can further improve the growth promotion performance of microorganisms of the conventional yeast extract, and furthermore, the color of the solution is lighter than that of the conventional product, and the appearance color is visually apparent. Is also good. Therefore, according to the microorganism detection medium of the present invention, the determination of positive or negative can be performed with high accuracy even when the sample is small. In addition, the medium for detecting microorganisms of the present invention is economically advantageous because it uses a less expensive torula yeast extract as compared to conventionally used beer yeast extract and baker's yeast extract.

[0017]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

Embodiment 1 FIG. Detection of microorganisms using standard agar medium The medium components shown in Table 1 were dissolved in 1000 ml of purified water,
After sterilization at 121 ° C. for 20 minutes, 20 ml of the mixture was poured into a Petri dish, and 1 ml of the bacterial solution precultured in a heart bouillon medium was diluted 10-fold to 10 ⁻⁶ and 10 ⁻⁷ , respectively, and inoculated with 1 ml by a pour method. After the medium was mixed and coagulated before coagulation, the cells were coagulated and cultured at 37 ° C. for 20 hours to measure the number of bacteria. As a control, the number of bacteria was compared in a medium using a conventional yeast extract. The results are shown in Tables 2 to 6. As shown in the table, the product of the present invention has a larger number of bacteria than the conventional product, so that determination of microorganisms becomes easier.

Table 1 Composition of standard agar medium 酵母 Yeast extract 2.5 g Tryptone 5 g Glucose 1 g Agar 15 g pH 7.1 ±

[0020] Table 2 ────────────────────────────── bacteria name Staphylococcus aureus EKN-1 inoculum 10 ^-6 10 ^{- 7} times 1 2 Average 1 2 Average Conventional 125 125 139 7 12 10 New 136 160 148 14 18 16

[0021] Table 3 ────────────────────────────── bacteria name Staphylococcus aureus EKN-2 inoculum 10 ^-6 10 ^{- 7} times 1 2 average 1 2 average Conventional product 84 87 86 6 8 7 New product 90 98 94 8 10 9

[0022] Table 4 ────────────────────────────── bacteria name Proteus vulgaris EKN-1 inoculum 10 ^-6 10 ^{- 7} times 1 2 Average 1 2 Average Conventional product 186 196 191 15 19 17 New product 194 197 196 22 22 23

[0023] Table 5 ────────────────────────────── bacteria name Proteus vulgaris EKN-2 inoculum 10 ^-6 10 ^{- 7} times 1 2 average 1 2 average Conventional 114 114 108 7 11 9 New 118 118 114 10 16 13

[0024] Table 6 ────────────────────────────── bacteria name Escherichia coli EKN-1 inoculum 10 ^-6 10 ^{- 7} times 1 2 Average 1 2 Average Conventional 114 114 108 7 11 9 New 118 118 111 111 10 12 11

Embodiment 2 FIG. Detection of microorganisms using TCBS agar medium The medium components shown in Table 7 were dissolved in 1000 mL of purified water,
After sterilization at 121 ° C for 20 minutes, the culture solution injected into a petri dish and solidified by a conventional method is inoculated with a strain obtained by serially diluting a bacterial solution pre-cultured with a heart bouillon medium to 10 ^-1 to 10 ^-6 by 10 times in a Misura method. After culturing at 37 ° C. for 20 hours, the growth of bacteria, the number of bacteria and the size of colonies were evaluated. As a control, the growth of bacteria, the number of bacteria and the size of colonies were compared in a medium using a conventional yeast extract. Tables 8 to 16 show the results. As shown in the table, the product of the present invention is superior to the conventional product in both the number of bacteria and the size of the colonies, and therefore, the determination is easy.

Table 7 Composition of TCBS agar medium ──────────────── Yeast extract 5 g Peptone 10 g Sucrose 20 g Sodium thiosulfate 7 g Sodium citrate 10 g Sodium cholate 3 g Bovine bile powder 5 g Sodium chloride 10 g Iron citrate 1 g Bromthymol blue 0.04 g Thymol blue 0.04 g Agar 15 g pH 8.8 ±

Table 8 ────────────────────────────────── Bacterial name Vibrio cholerae EKN-1 inoculated bacterial solution 10 ^-5 10 ^-6 colony Conventional product + 4 1.0 mm New product + 11 1.1 mm

Table 9 ────────────────────────────────── Bacterial name Vibrio cholerae EKN-2 inoculated bacterial solution 10 ^-5 10 ^-6 colony Conventional product +-1.0mm New product + 3 1.1mm

Table 10 菌 Bacterial name Vibrio cholerae EKN-3 Inoculated bacterial solution 10 ^-5 10 ^-6 colony Conventional product +2 1.8 mm New product +7 1.9 mm

Table 11 ────────────────────────────────── Bacteria name Vibrio cholerae EKN-4 inoculated bacterial solution 10 ^-5 10 ^-6 colony Conventional product + 4 1.1mm New product + 8 1.2mm

Table 12 ────────────────────────────────── Bacterial name Vibrio parahaemolyticus EKN-1 inoculated bacterial solution 10 ^-5 10 ^-6 colony Conventional product + 1 1.1mm New product + 5 1.2mm

Table 13 菌 Bacterial name Vibrio parahaemolyticus EKN-2 inoculated bacterial solution 10 ^-5 10 ^-6 colony Conventional product + 4 1.1mm New product + 10 1.2mm

Table 14 菌 Bacteria name Vibrio parahaemolyticus EKN-3 Inoculated bacterial solution 10 ^-5 10 ^-6 colony Conventional product + 6 1.1 mm New product + 10 1.2 mm

Table 15 ────────────────────────────────── Bacteria name Vibrio alginolyticus EKN-1 inoculated bacterial solution 10 ^-5 10 ^-6 colony Conventional product--Fine mm New product 11 4 2.2 mm

Table 16 ────────────────────────────────── Bacterial name Vibrio alginolyticus EKN-2 inoculated bacterial solution 10 ^-5 10 ^-6 colony Conventional product 12-2.1 mm New product 14 2 2.2 mm

Embodiment 3 FIG. Detection of microorganisms using Gandida GS agar medium Except for using the medium components shown in Table 17, the bacterial growth, the number of bacteria, and the size of colonies were evaluated in exactly the same manner as in Example 2. The results are shown in Tables 18 to 25. As shown in the table, the product of the present invention is superior to the conventional product in both the number of bacteria and the size of the colonies, so that the determination is easy.

Table 17 Composition of Gandida GS agar medium ──────────────── Yeast extract 4.5 g Peptone 10 g Glucose 20 g Nitrofuran derivative 0.5 g Agar 15 g pH 6.0 ±

[0038] Table 18 ────────────────────────────── bacteria name candido albicans EKN-1 inoculum 10 ^-5 10 ^{- 6} colonies Conventional product 3 2 1.5 mm New product 8 6 1.6 mm

[0039] Table 19 ────────────────────────────── bacteria name candido albicans EKN-2 inoculum 10 ^-5 10 ^{- 6} colonies Conventional 4-1.1mm New 6 4 1.2mm

[0040] Table 20 ────────────────────────────── bacteria name candido albicans EKN-3 inoculum 10 ^-5 10 ^{- 6} colonies Conventional 12 1 1.2mm New 16 4 1.3mm

[0041] Table 21 ────────────────────────────── bacteria name candido albicans EKN-3 inoculum 10 ^-5 10 ^{- 6} colonies Conventional 12 1 1.2mm New 15 4 1.3mm

[0042] Table 22 ────────────────────────────── bacteria name candido albicans EKN-4 inoculum 10 ^-5 10 ^{- 6} colonies Conventional product + 3 1.0mm New product + 6 1.1mm

[0043] Table 23 ────────────────────────────── bacteria name candido albicans EKN-5 inoculum 10 ^-5 10 ^{- 6} colonies Conventional product 6-2.0mm New product 9 3 2.1mm

[0044] Table 24 ────────────────────────────── bacteria name candido albicans EKN-6 inoculum 10 ^-5 10 ^{- 6} colonies Conventional product 14 2 1.1mm New product 18 7 1.2mm

[0045] Table 25 ────────────────────────────── bacteria name candido pseudotropicalis EKN-1 inoculum 10 ^-5 10 ^{- 6} colonies Conventional product--1.3 mm New product 6 2 1.4 mm

[0046] Table 26 ────────────────────────────── bacteria name candido glabrata EKN-1 inoculum 10 ^-5 10 ^{- 6} colonies Conventional product 4-1.5 mm New product 8 3 1.6 mm

Embodiment 4 FIG. Color of medium when torula yeast extract is used The medium components shown in Table 27 are dissolved in 1000 mL of purified water, sterilized at 121 ° C. for 20 minutes, and the color of the medium solution is measured using a spectrophotometer manufactured by Hitachi, Ltd. Measured at 420 nm.
The color of the solution was similarly measured using a conventional yeast extract as a control. As a result, the value of the conventional product was 0.480, while that of the product of the present invention was 0.353. As shown in the results, the product of the present invention has a lighter solution color than the conventional product, so that not only the number of bacteria and the growth of bacteria can be easily determined, but also the appearance color is good.

Table 27 Composition of agar medium 酵母 yeast extract 5 g peptone 15 g glucose 5 g sodium thioglycolate 0.5 g L-cystine 0.5 g sodium chloride 5g pH 7.1 ±

[0049]

Claims (3)

[Claims] 1. A medium for detecting microorganisms, comprising a Torula yeast extract as an active ingredient. 2. The content of torula yeast extract is 0.001 to 0.001.
The medium for detecting microorganisms according to claim 1, wherein the medium is in a range of 0.01 g / ml. 3. The microorganism detection medium according to claim 1, which is in the form of a plate solid medium.