Isolation and Characterization of non-O157 Shiga Toxin-Producing Escherichia coli in Aswan Governorate with a Zoonotic Approach

Abstract

Shiga toxin-producing Escherichia coli (STEC) infection has a significant negative influence on human wellness and the global economy. The purpose of this investigation was to identify E. coli and detect its virulence factors in dairy and meat products as well as, human diarrheal samples. A gross of 200 samples of raw milk, karish cheese, fresh meat, and minced meat were obtained randomly from different localities in Aswan Governorate, Egypt. In addition, 50 diarrhea samples were gathered from outpatients who admitted to medical labs and hospitals in Aswan Governorate. The samples were examined for the presence of non-O157 STEC using different biochemical tests and serotyping. The presence of different virulence genes (hly, eae, stx1, stx2) in E. coli isolates was investigated using PCR. The results illustrated that 28.8% of the examined samples were tainted with E. coli with the acquisition of fresh meat (40%), followed by minced meat and raw milk (20% for each), and finally karish cheese (16%) although it possess the highest odd ratio (4.846, 1.897-12.379). Depending on serology, twenty different serotypes were detected in overall samples, from the public health point of view, O26, O103, O126, O145, O86, O114, O121, O113, O104, and O118 were serotyped from both food and human samples. The prevalence of E. coli in humans was 48%, with insignificant correlation with age, sex, and residence. But the area under the receiver operating characteristic curve (ROC) referring to residence as the riskiest factor to human infection (0.583, 0.424-0.743). Moreover, PCR results demonstrated that the most prevalent gene recognized in E. coli strains was eaeA (90%) followed by stx2 (30%), hlyA (30%), and stx1 (10%). In conclusion, our results highlight the risk for non-O157 STEC infections related to consumption of raw milk, karish cheese, fresh meat, and minced meat.