Novel differential and confirmation plating media for Shiga toxin-producing Escherichia coli serotypes O26, O103, O111, O145 and sorbitol-positive and -negative O157.
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.
Possé
Björn
B
Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, University of Ghent, Merelbeke, Belgium.
De Zutter
Lieven
L
Heyndrickx
Marc
M
Herman
Lieve
L
D000818:Animals; D002417:Cattle; D003470:Culture Media / Q000737:chemistry*; D004927:Escherichia coli Infections / Q000382:microbiology* / Q000662:veterinary*; D005243:Feces / Q000382:microbiology; D005516:Food Microbiology; D006801:Humans; D012703:Serotyping; D054323:Shiga-Toxigenic Escherichia coli / Q000145:classification* / Q000254:growth & development / Q000302:isolation & purification* / Q000378:metabolism; D013012:Sorbitol / Q000378:metabolism*
D003470:Culture Media; D013012:Sorbitol