Low contamination of Campylobacter spp. on chicken carcasses in Minas Gerais state, Brazil: Molecular characterization and antimicrobial resistance

Here, we evaluated Campylobacter contamination on chicken carcasses and phenotypic and genotypic profiles of antimicrobial resistance of the isolated strains. A total of 95 of samples were collected from 19 slaughterhouses from Minas Gerais - Brazil, and analyzed by MPN-PCR method. Campylobacter was found in 16.8% of samples with microbial load ranging from 60 to 184 MPN/carcass. All isolates were resistant to at least 5 (31.2%) of the antimicrobials screened using the disk diffusion method. Thr-86-Ile gyrA mutation, blaOxA-61 and tet(O) genes were found in 95%, 100% and 40% resistant isolates to ciprofloxacin, ampicillin and tetracycline, respectively. Almost all isolates (90%) showed the three genes required to synthesize the CmeABC efflux system. The use of efflux pump inhibitor (PAβN) resulted in a significant reduction in the MICs of antimicrobials (2-128 fold), indicating the importance of efflux systems in conferring antimicrobial resistance. Campylobacter were detected at low concentrations in Brazilian chicken carcasses. However, high-levels of antimicrobial resistance were observed and associated with several mechanisms. This study provides a baseline survey on contamination of Campylobacter in Brazilian chicken carcasses and its antimicrobial resistance, giving support for actions directed at reducing this pathogen in the food chain.