Characterization and Antibiotic Resistance Profile of E. coli O157:H7 Isolates in Water Buffalo Carcasses

Document Type : Original Article


Department of Food Hygiene and Technology, Faculty of Veterinary Medicine, University of Ondokuz Mayıs, 55200 Samsun, Türkiye.


In this study, from the buffaloes slaughtered in slaughterhouses in Giresun and Samsun provinces, seasonally skin, rectoanal mucosal swab (RAMS) and carcass swab samples were collected. In the breadth of this study, a total of 600 samples were examined for the presence of Escherichia coli O157:H7. E. coli O157:H7 prevalence is 2.5% in RAMS, 3.5% in skin samples and 2% in carcass samples, with an average of 2.66%. Some virulence gene expressions of the isolates are distributed as follows; 28% (7/25) for the stx1 gene, 56% (14/25) for stx2, 68% (17/25) for the hlyA gene and 100% (25/25) for eaeA. The rate at which the stx1 and stx2 genes are found at the same time is determined to be 5/25 (20%). The antibiotic resistance rate of isolates have been identified as ampicillin at 24%, cephalothin at 20%, trimethoprim/sulfamethoxazole at 16%, gentamicin at 16%, streptomycin at 16%, tetracycline at 8%, amoxicillin at 4% and ciprofloxacin at 4%. It can be concluded that water buffalos, like cattle, are reservoirs of E. coli O157:H7, because of cross-contamination as a result of infections from feces to the carcass, feces to the skin, and skin to the carcass. The isolates containing the genes stx1, stx2, eaeA, and hlyA in actively contaminated water buffalo meat present the risk that major infection and death can occur in humans. Also resistance of isolates to antibiotics rates also indicates the unnecessary and uncontrolled use of antibiotics in the field of Veterinary Medicine.


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