Genotypic and Phenotypic Characterization of Antimicrobial Resistance and Virulence in Campylobacter spp. Isolated from Turkeys: Uncovering a Neglected Reservoir in the One Health Context.

Abstract

Background:Campylobacter spp. are leading foodborne pathogens, with increasing antimicrobial resistance (AMR) posing a critical public health threat. While broiler chickens have been widely studied, turkeys represent an underexplored reservoir. The present study investigates Campylobacter spp. in turkeys, focusing on isolation frequency, resistance, and virulence within the context of One Health. Methods: A total of 182 cecal samples were collected from slaughtered turkeys in Romania. Isolation and identification of Campylobacter jejuni and C. coli followed ISO 10272-1:2017 guidelines. Antimicrobial susceptibility testing was conducted via broth microdilution, and molecular analyses using PCR targeted species identification, resistance determinants, and virulence-associated genes. Results:Campylobacter spp. were detected in 75.8% of samples, with C. jejuni and C. coli accounting for 54.3% and 45.7%, respectively. High resistance rates were observed to ciprofloxacin (89.9%) and tetracycline (85.5%), with moderate resistance to erythromycin and ertapenem. No resistance was found to gentamicin or chloramphenicol. Genotypic analyses confirmed the presence of resistance genes (e.g., tetO, gyrA-Thr-86-Ile mutation, ermB, cmeB) and widespread virulence genes (flaA, cadF, cdtAB, ciaB), supporting phenotypic results. Conclusions: The survey highlights turkeys as a significant but neglected source of resistant and virulent Campylobacter spp., with implications for food safety and public health. The convergence of AMR and virulence aspects calls for integrated surveillance and control strategies across veterinary and human health sectors, supporting the One Health strategy.