Detection of Escherichia coli O157:H7 in heifers' faecal samples using an automated immunoconcentration system |
| |
Authors: | Vernozy-Rozand C Feng P Montet M P Ray-Gueniot S Villard L Bavai C Meyrand A Mazuy C Atrache V |
| |
Affiliation: | Unité de Microbiologie Alimentaire et Microbiologie Prévisionnelle, Ecole Nationale Vétérinaire de Lyon, Marcy l'Etoile, France. c.vernozy@vet-lyon.fr |
| |
Abstract: | Pre-treatment of a 5-h enrichment culture with an automated immunoconcentration (ICE) system greatly improved the isolation of Escherichia coli O157:H7 from spiked heifer faecal samples. Enrichment samples plated directly onto sorbitol MacConkey agar (SMAC) and SMAC agar supplemented with cefixime and potassium tellurite (CT-SMAC) showed recovery rates of 8% and 56%, respectively. However, after ICE treatment, E. coli O157:H7 was recovered from 92% of the samples on SMAC and 100% on CT-SMAC. Immunoconcentration analysis of heifers' faecal samples collected from a slaughter-house in France, during March to June 1998, showed that 1% (three of 300) was positive for E. coli O157:H7. Phenotypic and genotypic analysis showed that all three isolates carried both the O157 and H7 antigens, did not ferment sorbitol or had beta-glucuronidase activity and carried trait virulence factors for E. coli O157:H7 (uidA allele, eaeA and pO157 plasmid). However, only one strain was toxigenic and this strain produced a single toxin, namely verotoxin 2. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|