Detection and quantitation of enterohemorrhagic Escherichia coli O157, O111, and O26 in beef and bovine feces by real-time polymerase chain reaction.

摘要: Enterohemorrhagic Escherichia coli (EHEC) O157:H7 and certain non-O157 EHEC serotypes (such as O26:H11, 026: NM, O111:118, O111:NM) have emerged significant causes of human disease throughout the world. Important virulence attributes are intimin protein (encoded by eae gene) Shiga toxins 1 2 stxl stx2 genes, respectively). Two sets real-time polymerase chain reaction (R-PCR) assays were developed for simultaneous detection quantitation through monitoring presence stx these evaluated. In R-PCR assay, three primers TaqMan probes designed amplification a portion gene specific to O26, O111, 0157 serotypes. two used amplify detect genes. DNA prepared from 67 bacterial strains carrying known markers was tested determine specificities assays. O157 - O111 -specific primer-probe identified only strains, respectively. The O26 set all 026 isolates some toxin-negative enteropathogenic E. rabbit diarrheagenic The. assay able identify those either or both toxin-encoding range linear over concentrations corresponding 10 3 8 CFU/ml an strain. Both quantify very low levels (1 CFU/g food feces) in feces ground beef enriched 16 h modified Trypticase soy broth. conclusion, eae- stx-based reliable sensitive methods rapid screening quantitative important cattle foods bovine origin.