Campylobacter Contamination and Antimicrobial Resistance in Retail Meat from Vietnam and Japan

Campylobacter is a major cause of foodborne illnesses worldwide; however, comparative data on its occurrence and antimicrobial resistance (AMR) in retail meat across Asian regions remain limited. Therefore, this study investigated the prevalence, quantitative burden, and genomic and phenotypic AMR characteristics of Campylobacter in retail chicken and pork from Vietnam and Japan. Multiplex real-time polymerase chain reaction without enrichment successfully detected Campylobacter and revealed country-specific patterns, with Vietnamese chicken showing a substantially higher contamination rate (43.9%) with a predominance of C. coli (20.7%; n = 82) and Japanese chicken exhibiting a lower contamination rate (33.3%) with a predominance of C. jejuni (47.6%; n = 21). Notably, pork contamination was rare (2.2%; n = 46). Culture-based isolation recovered five C. jejuni isolates and one C. coli isolate from Japan and three C. coli isolates from Vietnam, using a membrane filter method necessary to obtain Vietnamese strains because of heavy Escherichia coli overgrowth. Whole-genome sequencing identified widespread quinolone resistance-associated gyrA mutations and a multidrug-resistant C. coli genotype in Vietnamese isolates harboring chromosomal determinants conferring resistance to multiple antimicrobial classes. Phenotypic susceptibility testing revealed universal resistance to fluoroquinolones and tetracyclines, along with carbapenem resistance, in several Japanese isolates and cephalosporin resistance in C. coli isolates from both countries. Overall, our findings indicate a markedly high contamination rate and AMR burden in Vietnamese retail chicken meat and underscore the need for stringent Campylobacter surveillance and effective risk-mitigation strategies in high-prevalence regions.