Molecular Detection and Characterization of Virulence Genes in Escherichia coli Isolated from Drinking Water and Raw Food Sources

Poor hygeine resluts in elevated levels of bacterial contamination in drinking water and raw food. Escherichia coli (E. coli) is one good indicator that shows the level of contamination in community water supply. E. coli horbour pathogenic and antibiotic resistance genes that can results in morbity. The aims of the study is to assess pathogenicnity and antibiotic resistance prevailing in water and food samples collected from Kohat. Method:Twenty samples were collected and subjected to various tests, including biochemical assays and polymerase chain reaction (PCR) to identify E. coli. Antibiogram assays were performed using Kirby disc diffusion method. PCR was employed to identify virulence genes (Stx-1 and Stx-2). Results: 70% of samples were found to have bacteria in them, and the most common were E. coli and other Enterobacteriaceae. Additional testing of E. coli-positive samples confirmed positive TSI results but negative citrate and urease tests. Antibiotic susceptibility testing revealed that most of samples were completely resistant to penicillin, ampicillin, ceftazidime, and cefixime, while some samples showed suseptibility to amoxicillin plus clavulanic acid, cefoxitin, cefepime, cefoperazone + sulbactum, levofloxacin, ceftriaxone, ciprofloxacin , clarithromycin, azithromycin and doxycycline as per CLSI standards. Three of the isolates were subjected to PCR for the detection STX1 and STX2 genes that confirmed the presence of the Stx2 gene in the two E. coli isolates, while Stx-1 was absent. Sequence analysis of Stx-2 gene showed >98% identity with GenBank sequences. Conclusions: In conclusion, this study employed a comprehensive approach to identify E. coli as a harmful pathogen in drinking water and raw food. The utilization of phylogenetic analysis, and virulence factor detection, along with antibiotic resistance profiling, enhances our understanding of E. coli contamination in resource-limited settings, highlighting the urgent need for improved wastewater management and hygiene practices.