Survey on O157:H7 enterohemorrhagic Escherichia coli (EHEC) in cattle in Golestan province, Iran

Abstract

Background and Objectives: A diverse group of Escherichia coli are known as enterohemorrhagic Escherichia coli (EHEC) including O157:H7 and non-O157 EHEC. Enterohemorrhagic strains are related to severe clinical conditions in humans including hemorrhagic colitis and hemolytic uremic syndrome, and most of the recorded outbreaks occurred due to O157: H7 E. coli. The aim of the present study was to investigate the presence of O157:H7 E. coli among healthy cattle in Golestan province. Materials and Methods: Fecal samples were collected from 180 clinically healthy cattle in Golestan province. After primary enrichment, samples were streaked on sorbitol MacConkey agar supplemented with cefixime and potassium tellurite (CT-SMAC). Non-sorbitol fermenting (NSF) Escherichia coli isolates were subjected to serotyping using commercial O157 antisera and rf b O157 gene PCR. Isolates were additionally tested for major virulence factors of EHEC including stx1, stx2, eae and ehly by multiplex-PCR. Results: Eighteen NSF isolates were recovered from CT-SMAC confirmed as E. coli in biochemical tests. None of the obtained isolates belonged to O157 serogroup. Overall, two isolates harbored the tested virulence genes; one isolate possessed stx2 and ehly, and the other one carried stx2, eae and ehly. Conclusion: The results of this study indicated that cattle in Golestan province could be the reservoir for non-O157 EHEC.

Keywords

• Cattle
• Golestan province
• O157
• H7
• PCR