Selective culture media for Pseudomonas spp. and their utilization

Abstract

By using a selective culture medium for Pseudomonas bacteria and a detection method and selection method for Pseudomonas bacteria, Pseudomonas bacteria such as Pseudomonas aeruginosa can be specifically and quantitatively detected; the selective culture medium for Pseudomonas bacteria is characterized by containing one or more third-generation cephalosporins and one or more antibiotics selected from the group consisting of first-generation cephalosporins and glycopeptide antibiotics in the basal culture medium.

Description

[Technical Field] This invention relates to a selective culture medium for Pseudomonas bacteria, a method for detecting Pseudomonas bacteria using the same medium, and a method for selecting Pseudomonas bacteria. [Previous Technology] Pseudomonas aeruginosa, a bacterium belonging to the genus Pseudomonas, poses a very low risk of causing infection in healthy individuals. However, in patients whose resistance has been reduced due to surgery, cancer treatment, transplantation, etc., it is a bacterium that can cause postoperative infections, ventilator-associated pneumonia, or severe bacteremia. In general medical institutions, the detection of Pseudomonas bacteria is performed using culture methods (Non-Patent Literature 1). However, selective media such as CHROM plates or NAC plates used in culture methods may sometimes detect bacteria other than Pseudomonas; moreover, the selective factors contained in the media may also have an antimicrobial effect on Pseudomonas, leading to an underestimation of bacterial count. Therefore, although qualitative testing can be performed, it is not easy to assess the degree of infection or contamination based on bacterial count. Therefore, in order to properly select antibiotics and carry out early treatment by means of culture methods, there is a need for novel selective culture media that can specifically and accurately quantify Pseudomonas bacteria. Furthermore, among Pseudomonas bacteria, Pseudomonas aeruginosa is particularly noteworthy. Reports indicate that 1) this bacterium is frequently isolated from the blood, sputum, and feces of hospitalized patients; and 2) a large number of patients exhibit asymptomatic infection (patients in a carrier state without symptom of infection), with the intestines becoming a source of infection and thus expanding the spread of the bacteria. Quantitative detection of Pseudomonas aeruginosa in feces could significantly help inhibit the spread of infection. [Previous Art Literature] [Non-Patent Literature] [Non-patent document 1] Sigurdardottir K, Digranes A, Harthug S, Nesthus I, Tangen JM, Dybdahl B, Meyer P, Hopen G, Lokeland T, Grottum K, Vie W, Langeland N. (2005) A multi-centre prospective study of febrile neutropenia in Norway: microbiological findings and antimicrobial susceptibility. Scand J Infect Dis 37: 455-64. [Summary of the Invention] [The problem that the invention aims to solve] As described above, the present invention aims to provide a selective culture medium for the specific and quantitative detection of Pseudomonas spp. bacteria such as Pseudomonas aeruginosa. [Means for Solving the Problem] The inventors of this invention, through their dedicated research to solve the aforementioned problems, discovered that by combining specific antibiotics in a basal culture medium, Pseudomonas bacteria can be selectively cultured, thus completing this invention. That is, the present invention is a selective culture medium for Pseudomonas bacteria, characterized in that the basal culture medium contains one or more third-generation cephalosporins and one or more antibiotics selected from the group consisting of first-generation cephalosporins and glycopeptide antibiotics. Furthermore, the present invention relates to a method for detecting Pseudomonas bacteria, characterized by inoculating a sample into a selective culture medium for the aforementioned Pseudomonas bacteria and culturing it to detect Pseudomonas bacteria. Furthermore, this invention relates to a method for selecting Pseudomonas bacteria, characterized by inoculating a sample into a selective culture medium for Pseudomonas bacteria and then culturing it to selectively culture Pseudomonas bacteria. [Effects of the Invention] The selective culture medium for Pseudomonas bacteria of the present invention can selectively culture Pseudomonas bacteria such as Pseudomonas aeruginosa, thereby enabling the specific and quantitative detection of Pseudomonas bacteria from the sample. Therefore, the present invention can be used to appropriately select antibacterial drugs and carry out early treatment in medical institutions.

Implementation Method

Claims

1. A selective culture medium for Pseudomonas bacteria, characterized in that the basal medium contains one or more third-generation cephalosporins, a first-generation cephalosporin, and a glycopeptide antibiotic, wherein the first-generation cephalosporin is a thiophene cephalosporin, the glycopeptide antibiotic is vancomycin, the basal medium is a mixture of NAC medium and TSA medium in a mass ratio of NAC:TSA of 1:1 to 20, the concentration of the third-generation cephalosporin in the basal medium is 0.1 μg / ml or higher and not exceeding 64 μg / ml, the concentration of the thiophene cephalosporin is higher than 16 μg / ml, the concentration of vancomycin is higher than 128 μg / ml, and the Pseudomonas bacteria is Pseudomonas aeruginosa.

2. Selective culture medium for Pseudomonas bacteria as requested in item 1, wherein the third-generation cephalosporin is cefuroxime or ceftiofur.

3. The selective culture medium for Pseudomonas bacteria as requested in item 1, wherein the third-generation cephalosporin is cefotaxime, and the concentration of cefotaxime in the basal culture medium is above 0.1 μg / ml but below 64 μg / ml.

4. The selective culture medium for Pseudomonas bacteria as requested in item 1, wherein the third-generation cephalosporin is ceftiofur, and the concentration of ceftiofur in the basal culture medium is above 0.1 μg / ml but below 16 μg / ml.

5. A method for detecting Pseudomonas bacteria, characterized in that a sample is inoculated into a selective culture medium for Pseudomonas bacteria as claimed in any one of claims 1 to 4 and cultured to detect Pseudomonas bacteria, wherein the Pseudomonas bacteria is Pseudomonas aeruginosa.

6. The method for detecting Pseudomonas bacteria as requested in item 5, wherein the sample is feces.

7. A method for selecting Pseudomonas bacteria, characterized in that a sample is inoculated into a selective culture medium for Pseudomonas bacteria as claimed in any one of claims 1 to 4 and cultured to selectively culture Pseudomonas bacteria, wherein the Pseudomonas bacteria is Pseudomonas aeruginosa.

8. The method for selecting Pseudomonas bacteria as requested in item 7, wherein the sample is feces.