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


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.


CONCLUSIONS
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.
Evans
J
J
SAC Epidemiology Research Unit, Animal Health Group, SAC Research, Edinburgh, UK. judith.evans@sac.ac.uk
Knight
H I
HI
Smith
A W
AW
Pearce
M C
MC
Hall
M
M
Foster
G
G
Low
J C
JC
Gunn
G J
GJ
D000362:Agar; D000818:Animals; D002417:Cattle / Q000382:microbiology*; D020682:Cefixime / Q000494:pharmacology*; D003470:Culture Media; D005243:Feces / Q000382:microbiology*; D005285:Fermentation; D012210:Rhamnose / Q000378:metabolism*; D012756:Sheep / Q000382:microbiology*; D054323:Shiga-Toxigenic Escherichia coli / Q000302:isolation & purification* / Q000378:metabolism; D013691:Tellurium / Q000494:pharmacology*
D003470:Culture Media; D000362:Agar; D020682:Cefixime; C026660:tellurous acid; D013691:Tellurium; D012210:Rhamnose