Virulence, MLST analysis, and antimicrobial resistance of Campylobacter coli isolated from broiler chickens in Tamil Nadu, India.

Abstract

Campylobacter species are the zoonotic bacteria and the most common cause of foodborne gastroenteritis around the world. The link between human campylobacteriosis and infected poultry consumption has been well established. In this study, we aimed to isolate Campylobacter spp. from chicken and characterize them with molecular methods. Totally, 241 chicken caecal mucosal scrapings were collected from five districts of Tamil Nadu. Bacterial isolation was done by plating on blood-free Campylobacter selective medium with supplements. Campylobacter species were identified by multiplex PCR and Campylobacter coli isolates were tested for 11 virulence genes by PCR. C. coli isolates were typed based on seven housekeeping genes multilocus sequence typing (MLST) scheme. The antimicrobial susceptibility was determined by a microdilution resazurin assay. The prevalence of C. coli and C. jejuni were 14.94% (36/241), and 3.32% (8/241), respectively. The virulence genes flaA, flaB, cadF, cdtA, cdtB, cdtC, ciaB, and ceuE were present in all 36 C. coli isolates, pldA and racR genes were present in 58.33% (21/36), and 16.67% (6/36) of the isolates, respectively, and dnaJ was present in only one isolate. Two novel sequence types (ST-10872, ST-11031) were found in this study. Though different STs were identified, all the STs belonged to the same clonal complex of ST-828. All 14 C. coli isolates showed 100% resistance to nalidixic acid, and higher resistance to tetracycline (92.8%), erythromycin (71.4%), clindamycin (71.4%), and azithromycin (64.2%) was noticed. All C. coli isolates were sensitive to chloramphenicol, and higher sensitivity to ciprofloxacin (78.5%), and gentamicin (71.4%) was observed. The present study demonstrated that C. coli is more prevalent in broilers than C. jejuni in Tamil Nadu. The presence of C. jejuni and C. coli in chicken caecal samples from the slaughterhouse are indicative of the possibility of public health hazards.