Novel differential and confirmation plating media for Shiga toxin-producing Escherichia coli serotypes O26, O103, O111, O145 and sorbitol-positive and -negative O157

FEMS Microbiol Lett. 2008 May;282(1):124-31. doi: 10.1111/j.1574-6968.2008.01121.x. Epub 2008 Mar 18.

Abstract

This study reports two novel selective differential media. A first differential medium can be applied in methods for the isolation of non-O157 Shiga toxin-producing Escherichia coli (STEC) serotypes (O26, O103, O111 and O145) from food or faeces. A second differential medium was designed for both sorbitol-positive and -negative O157 STEC strains. Selective differential media are based on a chromogenic compound to signal beta-galactosidase activity and one or more fermentative carbon sources. The chromogenic marker and carbohydrates were combined with a pH indicator and several inhibitory components, which resulted in highly specific differentiation media. Consecutive use of a serotype-dependent choice of confirmation media resulted in a very low incidence of false-positive isolates when comparing clinical STEC strains with a collection of commensal E. coli strains.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cattle
  • Culture Media / chemistry*
  • Escherichia coli Infections / microbiology*
  • Escherichia coli Infections / veterinary*
  • Feces / microbiology
  • Food Microbiology
  • Humans
  • Serotyping
  • Shiga-Toxigenic Escherichia coli / classification*
  • Shiga-Toxigenic Escherichia coli / growth & development
  • Shiga-Toxigenic Escherichia coli / isolation & purification*
  • Shiga-Toxigenic Escherichia coli / metabolism
  • Sorbitol / metabolism*

Substances

  • Culture Media
  • Sorbitol