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The Journal of the Japanese Society for Clinical Microbiology |
Biblioraphy Information
| ArticleTitle |
Development of Chromogenic Selective Medium: Vital Media CIX Agar for Differentiation of Enterohemorrhagic Escherichia coli |
| Language |
J |
| AuthorList |
Maki Kitagawa, Suguru Ichiishi, Shigeaki Kasahara, Hiroshi Enari |
| Affiliation |
Kyokuto Pharmaceutical Industrial Co., Ltd., Kamitezuna, Takahagi, Ibarakki 318-0004, Japan |
| Publication |
J.J.C.M.: 22 (3), 214-220, 2012 |
| Received |
September 22, 2011 |
| Accepted |
June 28, 2012 |
| Abstract |
We describe here the development of Vital media CIX agar (CIX agar), a new chromogenic agar medium for the specific isolation and identification of Enterohaemorrhagic Escherichia coli (EHEC) such as major serotype O157, O26 and O111. Colonies of E. coli O157 growing on CIX agar produce a mauve color and colonies of E. coli O26 and O111 growing on CIX agar produce ultramarine color due to two chromogenic substrates in the medium, thus allowing presumptive identification from the primary isolation plate and differentiation from other organisms. The addition of pH indicator and cellobiose which indicated for differentiation of E. coli in the CLIG agar has decreased growth of other bacteria such as homologous colony presented. We evaluated the use of this medium with 27 EHEC isolates and 2 verotoxin non-producing O157 isolates. The 13 Cefixime-tellurite (CT) resistant EHEC isolates presented determinate colors, however the 16 CT sensitive EHEC isolates growth inhibition or weak growth caused by CT. E. coli and 13 Enterobacteriaceae were inhibited by CT, except for Escherichia hermannii. Investigation of 40 stool specimens showed that pigmented normal flora was Klebsiella spp. and Enterobacter spp. However, all strains of EHEC grew abundantly and were easily distinguished on CIX agar as typical colonies.
We concluded that CIX agar is a sensitive and specific medium for the isolation and identification of EHEC such as major serotype O157, O26 and O111. |
| Keywords |
Cefixime-tellurite |
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