DETECTION OF EHXA, STX1AND STX2 VIRULENCE GENES IN NON-O157 ESCHERICHIA COLI ISOLATED FROM CATTLE BY MULTIPLEX POLYMERASE CHAIN REACTION AND THE DETERMINATION OF ANTIBIOTIC RESISTANCE PROFILE OF THESE ISOLATES

Shiga toxigenic Escherichia coli is one the most important bacteria within Bacteriacae. The bacteria infect humans and a wide spectrum of animals, resulting in dangerous consequences such as hemolytic uremic syndrome and hemorrhagic colitis. In the current study, the prevalence of hemolysin (ehxA) and Shiga toxin (stx1 and stx2) virulence genes in non-O157 Escherichia coli, isolated from cattle stool samples, was evaluated by Multiplex PCR. The animals were referred to the Large Animal Teaching Hospital of the Faculty of Veterinary Medicine, University of Tehran. The antibiotic resistance profiles of the isolates were assessed against seven usual antibiotics used in veterinary medicine. In the PCR study of 39 non-O157 Escherichia coli strains isolated from cattle stool samples, 10 samples were found positive for stx1 or stx2 genes. The prevalence of ehxA gene was zero,which is significantly lower than that mentioned in papers reporting on this issue. As expected, the prevalence rate of stx genes in cattle isolates was usual (nearly 25%). The prevalence of stx2 was greater than the prevalence of stx1. All isolates were multiple resistant to two or more antibiotics, including ampicillin, erythromycin, polymixin B, tetracycline, trimethoprim-sulfamethoxazole, gentamicin and/or cephalotin.