Molecular Characteristics and Pattern of Antibiotic Resistance of Common <i>Escherichia coli</i> Pathotypes Isolated From Wastewater of Slaughterhouses

Background: Wastewater from slaughterhouses serves as a reservoir for various Escherichia coli pathotypes, including enterotoxigenic (ETEC), enteropathogenic (EPEC), and enterohemorrhagic (EHEC) strains, which pose significant public health risks. This study aimed to isolate and molecularly identify common E. coli pathotypes in slaughterhouse wastewater and assess their antibiotic resistance patterns. Methods: A total of 58 E. coli isolates were collected from wastewater samples at local slaughterhouses. The isolates were subjected to molecular identification using a polymerase chain reaction targeting specific virulence genes associated with E. coli pathotypes. Antibiotic susceptibility testing was performed using the disk diffusion method against commonly used antibiotics. Results: The analysis of virulence genes in E. coli isolates revealed significant insights into the pathogenicity and potential health risks associated with these bacteria. A total of 58 isolates were analyzed for the presence of virulence genes. Among these, 20 (34.4%) were positive for the eae gene (EPEC), 5 (8.6%) for stx1 + stx2 (EHEC), and 4 (6.8%) for estA2-4 (ETEC). No isolates were positive for the elt gene. Additionally, 29 isolates (50.2%) did not carry any of the targeted virulence genes (eae, stx1 + stx2, estA2-4, or elt). The antibiotic resistance profile of E. coli isolates demonstrated significant resistance rates to commonly consumed antibiotics. Among the 58 isolates, resistance was observed to streptomycin (63.7%), kanamycin (39.6%), imipenem (51.7%), and notably erythromycin (100%). Additionally, 92% of virulence gene-positive isolates were multidrug-resistant, with four isolates exhibiting extensive resistance to all tested antibiotics. Conclusion: The findings highlight the prevalence of pathogenic E. coli strains in slaughterhouse wastewater and their resistance to multiple antibiotics, underscoring the potential health risks they pose and the need for effective management strategies to mitigate their impact on public health.