PCR detection of Escherichia coli O۱۵۷:H۷ directed from slaughtered cattle in Shiraz, Iran

Escheric hia coli O۱۵۷:H۷ lives in the intestines of healthy cattle, and can contaminate meat during slaughtering pr actices . Detection of the low infectious dosage of bacterium requires a sensitive method. We developed polymerase chain reaction (PCR) assays to detect the gene Stx۲ irrespective of the bacterial serotype. In this study, the detection limit of the PCR protocol in detecting Stx۲ in E. coli O۱۵۷:H۷ without prior enrichment was ۱۰۳ CFU/ml, and with ۴ h prior enrichment in modified tryptic soy broth was ۱۰۲ CFU/ml. During a period of ۷ months (December ۲۰۰۴ to June ۲۰۰۵), ۱۵۴ slaughtered cattle at Shiraz slaughterhouse, were randomly selected and examined for surface carriage of E. coli O۱۵۷:H۷ via detection the Stx۲ gene of verotoxigenic E. coli by PCR technique. E. coli O۱۵۷:H۷ was found in ۱۴ of ۱۴۵ (۹.۶۵%) feedlot cattle and in ۱ of ۹ (۱۱.۱%) dairy cull cows. This is the first report of the presence of E. coli O۱۵۷:H۷ in cattle from Iran.

Keywords:

Escherichia coli O۱۵۷: H۷ , Stx۲ , Cattle , PCR