Prevalence of Shiga Toxins, Intimin and Hemolysin Genes of Escherichia coli O157:H7 Strains from Industrial Ground Meat in Shiraz

Escherichia coli O157:H7 is one of the major foodborne illness and sporadic case of human disease, hemorrhagic colitis and hemolytic-uremic syndrome. The purpose of this study is to survey the prevalence of Escherichia coli O157:H7 virulence genes from ground meat in Shiraz. In this research 504 samples of ground meat were collected from three main factories of meat products and enriched in Escherichia coli broth with novobiocin medium in 37ºC. Fermentation of sorbitol and lactose and β-glucoronidase activity of isolated strains were examined by CT-SMAC, VRBA and chromogenic media respectively. Then isolation of E.coli O157:H7 have been confirmed with the use of specific antisera and with multiplex PCR method presence of E.coli O157:H7 virulence genes including: stx1, stx2, eaeA, hly has been analysed. Out of specimens that have been supplied, 466 sorbitol negative bacteria were isolated in CT-SMAC medium(92.46%). The stx1 and eaeA genes were diagnosed in two case of these samples(0.39 %) and stx2 gene was detected in one case(0.19%) of isolated E.coli O157:H7 strains. E.coli O157:H7 will continue to be an important public health concern as long as it contaminates meat. Preventive measures may reduce the number of cattle that carry it and the contamination of meat during slaughter and grinding.