Prevalence of Virulence Factors and Antibiotic Resistance Genes in Shiga Toxin-Producing Escherichia Coli Isolated From Quails

Abstract

This study aimed to determine the prevalence, pathological investigation and profiles of virulence and antibiotic resistance genes in Shiga toxin-producing Escherichia coli (E. coli) isolated from quails. A total of 450 samples were collected from 150 quails (50apparently healthy, 50 diseased and 50 recently dead) for bacterial isolation. The isolated E.coli was tested for antimicrobial susceptibility and was screened for the presence of virulence genes (stx1, stx2, eaeA, and hly) and antibiotic resistance genes (tetAandsul1) using polymerase chain reaction (PCR). Seven-day old quails were challenged with E. coli to determine the pathogenicity of the isolated strains. A total number of 93 (20.67%) E. coli isolates were recovered. The most prevalent serogroups O125, O20, and O78. E. coli were highly sensitive to neomycin, norfloxacin, and, colistin, highly resistant to sulphamethoxazole, tetracycline, and amoxicillin. Stx2 and eaeA genes were detected in (3/8) and (2/8) of isolates, respectively, while all isolates were negative for stx1 and hly genes. Moreover, tetA and sul1 genes were detected in 100% of examined isolates. The pathogenicity test revealed that E .coli (O125 STEC) was a highly pathogenic and induced mortality rate of 40%. Histopathological changes supported the post mortem lesions. In conclusion, these data can be considered alarming since quail may be a carrier of STEC that is highly pathogenic for humans. Also, these E. coli showed marked resistance to several antibiotics of clinical interest. So proper hygiene regime and biosecurity measures are necessary to minimize the risk of spread of infection to the human population.