Molecular Typing of Virulence and Antimicrobial Resistance Genes with Mutation Tracking of gyrA Gene of Fluoroquinolone-Resistant Strains of Campylobacter Isolated from Broiler Chickens

Abstract

 Campylobacter is the most common bacterial cause of gastroenteritis globally. A total of 182 fully identified strains of Campylobacter species (42 C. coli and 140 C. jejuni) collected from 6 broiler farms were subjected to studying the antimicrobial resistance pattern and molecular typing of virulence (cadF, ctdA, dnaJ waaC,iam, and fla) and antimicrobial resistance genes (bla_OXA-61, gyrA, tetA, tetO, and IR) with sequencing of gyrA region of one strain of fluroquinolones resistant C. coli and C. jejuni. The identified isolates were highly resistant to erythromycin and sulfamethoxazole-trimethoprim. Furthermore, both meropenem and imipenem were effective against the recovered isolates. The tested C. jejuni and C. coli strains had 100%, 83.3%, and 83.3% prevalence of cadF, ctdA, and dnaJ virulence genes, respectively, while waaC, iam, and fla genes couldn’t be detected. The bla_OXA-61 resistance gene was found in all of the Campylobacter spp. examined. Furthermore, gyrA, tetA, tetO, and IR resistance genes were found in 100%, 83.3%, 83.3%, and 66.7% of the retrieved C. jejuni strains, respectively.  Likewise, resistance genes were found in 83.3%, 83.3%, 83.3%, and 66.7% of the retrieved C. coli strains, respectively. Approximately 58% (7/12) of the Campylobacter spp. recovered were MDR. Furthermore, 50% (3/6) of the C. jejuni strains recovered were MDR, while 66.7% (4/6) of the C. coli isolates recovered were MDR with MARI(0.22-0.55). For detection of mutations of the gyrA gene, the sequence data of two isolates (C. jejuni and C.coli) were analyzed against the reference sequence on the gene bank where the C. jejuni strain had six mutations, while the C. coli strain had twenty-three. The current findings suggest that MDR Campylobacter strains in poultry may be able to transmit highly virulent Campylobacter as a foodborne pathogen.