Escherichia coli O157 is recognized as an important foodborne pathogen responsible for sporadic cases to serious outbreaks worldwide. The morbidity and mortality associated with several recent outbreaks due to STEC have highlighted the threat this organism possess to public health. Bacteriological examination of (671) samples collected from cattle, sheep, chickens, ducks, milk and water showed that 34.3% (230/671) were positive E. coli. Out of (230) isolates of positive E. coli, (16) isolate were identified by vitek2 system as E. coli O157 (6.9%) with high incidence in cattle samples (20%) then chicken and water samples (13.6%) and (12.5%) respectively. On the other hand, there were no isolates from ducks samples for E. coli O157 and with low percent (7.8%) from raw milk samples and (1%) from sheep samples. The application of PCR for screening of virulence genes (sxt1, sxt2 and eaeA) in E. coli O157 isolates revealed that out of (16) isolates of E. coli O157 there were (9), (6) and (16) were positive for stx1, stx2 and eaeA, respectively. This study concluded that molecular identification by PCR for detection of E. coli O157 virulence genes is rapid, specific and accurate approach in studying the actual role of these genes in disease pathogenicity.
Key words: E.coli O157, virulence factor and sequence of eaeA gene).
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