Abstract
Abstract: Among the bacterial pathogens that affect the health of the population, the safety of the food, and the quality of the environment, Escherichia coli is one of the most impactful. The distribution of virulence genes across isolates from varying sources gives crucial information on possible pathways of transmission and associated public health threats. The risk profiling of potential pathogen reservoirs is constructed barring the recurrent molecular probes of the pathogen. The present study aims to analyze the virulence of E. coli genes in three different sources, clinical, food, and environment, using a core set of verified RT-PCR virulence markers. The study involved 150 isolates including 50 clinical samples of patients with gastrointestinal complaints, 50 food samples from a dairy, meat and vegetable mixture, and 50 environmental samples from collected water and soil. Each of the isolates was targeted for a set of major virulence factors (elt, est, aggR, ipaH, eae, bfpA, stx1, stx2 and rfbE) using literature real time PCR primers perfected for greater precision. The gene presence was compared among the three groups and the distribution of the gene, and the differences bounded in the gene to determine which one of the groups was the most predominant in the pathogenic traits. Clinical isolates had the most significant (p<0.05) total virulence burden due to their presence of eae, ipaH, stx1, and stx2. Food isolates had moderate presence of elt, est, and aggR, revealing the probable contamination of the food supply. Environmental isolates had the least (p<0.05) amount of virulence factors, but some of them had eae and stx2, suggesting that they are undetected reservoirs of pathogenic strains. The differences in virulence gene distribution in the three of them were significant and demonstrated evident source-related patterns and major epidemiological consequences. The data indicate that the most virulent profiles are found in clinically sourced pathogens, while food and environmental sources also participate in the dissemination of pathogenic E. coli. The need to enhance surveillance and prevent cross-source dissemination is reinforced