EHEC O157∶H7 with virulence gene detected in Kecheng district, Quzhou city, Zhejiang province

Objective　The study was conducted to investigate the human infection, food contamination, and bacteria bearing of animal and insect vectors of enterohemorrhagic IEscherichia coli/I O157∶H7 in Quzhou, Zhejiang. Methods　Diarrhea patient and animal stool samples, various food samples and fly samples were cultured in MEC broth, amassed with immunomagnetic separation, and isolated in CHROMAGAR O157∶H7 culture medium. Purified isolates were biochemically identified, serotyped and detected for virulence genes. Results　A total of 300 animal stool samples were collected in 2007, and 16 strains of O157∶H7 were isolated with the overall positive rate of 5.33%. The positive rates of bacteria bearing cattle, sheep and pig were 20.83%, 12.70% and 3.61%, respectively. No O157∶H7 were isolated from the samples of diarrhea patients, food and insects. PCR results showed that stx2, hly and eaeA were positive and stx1 was negative in all isolates. Conclusion　Some animals in Kecheng county, Quzhou city were infected by toxin producing E.coli O157∶H7. Therefore comprehensive surveillance for O157∶H7 is required.