Antibacterial Resistance and Virulence Potential of Avian Colibacillosis-Causing Escherichia coli Isolates

Backgrounds: This study was done to evaluate the distribution of virulence-associated genes and antibiotic resistance in avian colibacillosis-causing Escherichia coli (E. coli) isolates. Materials Methods: In this study, 122 E. coli strains isolated from colibacillosis-suspected chickens in commercial broiler poultry farms (Guilan province, Iran) were examined for the presence of 12 virulence genes (hlyF, iroN, iss, iutA, ompT, astA, tra, sfa-foc, papC, fimH, cvi/cva, and Tia) using polymerase chain reaction (PCR). Antimicrobial susceptibility assessment was performed for the isolates using disc diffusion method against 19 antibiotics. Findings: The fimH, iut, tra, iss, iroN, hly, and ompT genes were detected as the most prevalent genes among colibacillosis-causing isolates (more than 70%), while sfa-foc (S fimbriae and F1C fimbriae subunits) had the lowest frequency among colibacillosis-causing E. coli isolates (3.28%). Conclusion: Virulence-associated genes were frequently detected in avian pathogenic E. coli strains. These findings could help better understand the pathogenicity potential of E. coli in poultry. Preventative measures are necessary to reduce food and environmental contamination with avian E. coli strains.