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The Journal of the Japanese Society for Clinical Microbiology |
Biblioraphy Information
| ArticleTitle |
Evaluation of chromogenic culture medium CHROMagar STEC in detection of Shiga toxin-producing Escherichia coli strains |
| Language |
J |
| AuthorList |
Hidemi Aoki1), Miwa Motani2), Mitsugu Yamazaki2), Susumu Sobue2), Yoshio Miwa2), Izumi Shibuya2), Haruki Koyasu1) |
| Affiliation |
1) Aichi Prefectural Handa Health Center
2) Aichi Prefectural Ichinomiya Health Center |
| Publication |
J.J.C.M.: 25 (2), 117-124, 2015 |
| Received |
May 26, 2014 |
| Accepted |
December 22, 2014 |
| Abstract |
The chromogenic culture medium CHROMagar STEC, launched recently, is thought to be a promising culture medium for screening and detection of strains belonging to major serogroups of Shiga toxin-producing Escherichia coli (STEC), based on development of its typical mauve colonies. This new culture medium strongly inhibits the growth of fecal coliforms and other bacteria. Of 123 STEC strains, 119 strains (96.7%) grew on CHROMagar STEC, but the remaining 4 strains did not grow on the medium. Of the 119 strains, 115 strains formed typical mauve colonies, 1 strain formed brown colonies, and 3 strains formed both mauve and white small-colonies on the plates.
As for 85 strains of STEC, the minimum inhibitory concentrations (MICs) of potassium tellurite were distributed in a wide range (≤0.2∼100<μg/ml). The MICs of the 7 strains, which did not grow well or formed small-colonies on CHROMagar, showed ≤3.13 μg/ml.
In conclusion, there is an inclination of the CHROMagar STEC medium to suppress the growth of STEC strains, which are sensitive to the potassium tellurite. A combined screening practice with CHROMagar STEC and selective media without potassium tellurite is recommended in order to reduce the risk for under-detection of the STEC strains. |
| Keywords |
CHROMagar STEC, MIC |
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