Drug-resistance and virulence in Campylobacter jejuni: insights from clinical, poultry, and wastewater interfaces

Abstract

Campylobacter jejuni is a leading cause of human gastrointestinal infections, primarily transmitted through the consumption of undercooked poultry, the main reservoir of Campylobacter species, and via cross-contaminated food and water. The emergence of multidrug-resistant (MDR) C. jejuni due to resistance to various antimicrobial agents poses significant global health risks. This research aims to characterize antimicrobial resistance patterns and virulence genes of C. jejuni from clinical, poultry and wastewater interfaces in Bangladesh. In this study, fifteen C. jejuni isolates were cultured on CHROMagar plates and subjected to phenotypic testing, polymerase chain reaction, and antimicrobial resistance assessment. The Kirby–Bauer disc diffusion method was used to evaluate resistance to nine antibiotic classes, while minimum inhibitory concentrations for ciprofloxacin, erythromycin, and tetracycline were determined by E-test. The isolates showed 100% resistance to ciprofloxacin and erythromycin; 93% to sulfamethoxazole, azithromycin, nalidixic acid, and ampicillin; 87% to ceftriaxone; 73% to cefuroxime; 67% to gentamicin, cefoxitin, and cefixime; 60% to tetracycline; 47% to ampicillin and chloramphenicol; 27% to imipenem; and 7% to amikacin. All isolates were resistant to more than four antibiotic classes, with wastewater isolates showing the highest resistance rates. Resistance to macrolides and fluoroquinolones, which are critical antibiotics for the treatment of Campylobacteriosis, was observed in all isolates. Virulence genes, including flaA, racR, cdtA, cdtC, gyrB, parC, and wlaN were investigated using gene-specific PCR. All five wastewater and clinical isolates assessed positive for flaA and parC. The genes racR, cdtA, and cdtC were present in four clinical isolates, while chicken isolates exhibited racR (1/5), cdtA (1/5), and cdtC (4/5). The wlaN gene was detected in one clinical, two chicken, and three wastewater isolates, while the gyrB gene was found in one wastewater and two chicken isolates. Overall, virulence gene prevalence was cdtA (53%), flaA (47%), wlaN (40%), cdtC (33%), racR (33%), parC (33%), and gyrB (20%). In Bangladesh, widespread self-medication with antibiotics and treatment failures due to resistance exacerbate the problem. However, MDR C. jejuni and their resistance patterns at the clinical-poultry-wastewater interface remain poorly studied. This study provided valuable insights into the antimicrobial resistance profiles and virulence determinants of MDR C. jejuni, a significant contributor to diarrheal mortality in Bangladesh, thereby enhancing understanding of its pathogenesis and implications for public health.