Detection of Escherichia coli O157:H7 in heifers' faecal samples using an automated immunoconcentration system

Autor: S. Ray-Gueniot, V. Atrache, C. Mazuy, C. Vernozy-Rozand, A. Meyrand, C. Bavai, M.P. Montet, P. Feng, L. Villard
Rok vydání: 2000
Předmět:
Zdroj: Letters in Applied Microbiology. 30:217-222
ISSN: 0266-8254
DOI: 10.1046/j.1472-765x.2000.00702.x
Popis: 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.
Databáze: OpenAIRE