Occurrence, virulence genes, and antimicrobial profiles of Escherichia coli O157 isolated from ruminants slaughtered in Al Ain, United Arab Emirates

Abstract

Background: Shiga toxin-producing Escherichia coli (STEC) is a major source of food-borne illness around the world. E. coli O157 has been widely reported as the most common STEC serogroup and has emerged as an important enteric pathogen. Cattle, in particular have been identified as a major E. coli O157:H7 reservoir of human infections; however, the prevalence of this organism in camels, sheep, and goats is less understood. The aim of this study was to evaluate the occurrence and concentration of E. coli serotype O157 in the feces of healthy camels (n = 140), cattle (n = 137), sheep (n = 141) and goats (n = 150) slaughtered in United Arab Emirates (UAE) for meat consumption between September 2017 and August 2018. We used immunomagnetic separation coupled with a culture-plating method to detect E. coli O157. Non-sorbitol fermenting colonies were assessed via latex-agglutination testing, and positive cultures were analyzed by performing polymerase chain reactions to detect genes encoding attaching and effacing protein (eaeA), hemolysin A (hlyA, also known as ehxA) and Shiga toxin (stx1 and stx2), and E. coli O157:H7 specific genes (rfb O157, uidA, and fliC). All E. coli O157 isolates were analyzed for their susceptibility to 20 selected antimicrobials. Results: E. coli O157 was observed in camels, goats, and cattle fecal samples at abundances of 4.3, 2, and 1.46%, respectively, but it was undetectable in sheep feces. The most prevalent E. coli O157 gene in all STEC isolates was stx 2 ;, whereas, stx 1 was not detected in any of the samples. The fecal samples from camels, goats, and cattle harbored E. coli O157 isolates that were 100% susceptible to cefotaxime, chloramphenicol, ciprofloxacin, norfloxacin, and polymyxin B. Conclusion: To our knowledge, this is the first report on the occurrence of E. coli O157 in slaughter animals in the UAE. Our results clearly demonstrate the presence of E. coli O157 in slaughtered animals, which could possibly contaminate meat products intended for human consumption.