Cefixime-tellurite rhamnose MacConkey agar for isolation of Vero cytotoxin-producing Escherichia coli serogroup O26 from Scottish cattle and sheep faeces

Lett Appl Microbiol. 2008 Sep;47(3):148-52. doi: 10.1111/j.1472-765X.2008.02402.x.

Abstract

Aims: To compare rhamnose MacConkey agar supplemented with cefixime and tellurite (CT-RMac) and tryptone bile X-glucuronide (TBX) agars as isolation media for Vero cytotoxin-producing Escherichia coli (VTEC) serogroup O26 from animal faeces.

Methods and results: Nine VTEC O26 were isolated from sheep faeces; out of which six were isolated only on CT-RMac and one was isolated only on TBX. One hundred and twelve VTEC O26 were isolated from calf faeces; out of which 97% were from CT-RMac and 52% were from TBX. In a study of E. coli O26 strains, 84% of VT-positive O26 did not ferment rhamnose when compared with 16% of VT-negative O26. VT-positive (19%) and VT-negative (39%) E. coli O26 strains did not grow on CT-RMac agar.

Conclusions: It is important to consider that VTEC O26 strains either may ferment rhamnose or may be sensitive to the CT supplement of CT-RMac agar.

Significance and impact of the study: This work compares CT-RMac and TBX agars as isolation medium for VTEC O26 from Scottish animal faeces and highlights that VTEC O26 may be missed if only CT-RMac agar is used.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Agar
  • Animals
  • Cattle / microbiology*
  • Cefixime / pharmacology*
  • Culture Media*
  • Feces / microbiology*
  • Fermentation
  • Rhamnose / metabolism*
  • Sheep / microbiology*
  • Shiga-Toxigenic Escherichia coli / isolation & purification*
  • Shiga-Toxigenic Escherichia coli / metabolism
  • Tellurium / pharmacology*

Substances

  • Culture Media
  • Agar
  • Cefixime
  • tellurous acid
  • Tellurium
  • Rhamnose