Prevalence and genetic characterization of Campylobacter spp., Salmonella spp. and Listeria monocytogenes in raw meat from Beijing, China, 2021-2023.

Foodborne pathogens such as Campylobacter spp., Salmonella spp., and Listeria monocytogenes are major contributors to foodborne illnesses. While numerous studies have reported their prevalence in raw meat, integrated analyses addressing multipathogen co-contamination and genomic relatedness in retail environments remain limited. In this study, we investigated the prevalence, co-contamination patterns, and genomic characteristics of these three pathogens in retail raw meat in Beijing, China (2021-2023). In total, 1052 raw meat samples (poultry, pork, beef, and mutton) were collected from farmers' markets and supermarkets. Whole-genome sequencing and core genome multilocus sequence typing (cgMLST) were applied to characterize the isolates. Overall, 214 (20.34%) samples were positive for Campylobacter spp., 260 (24.71%) for Salmonella spp., and 550 (52.28%) for L. monocytogenes. Poultry showed the highest positivity for Campylobacter spp. (35.49%) and Salmonella spp. (38.40%), whereas L. monocytogenes was prevalent across all meat types, although highest in pork (66.19%). Co-contamination occurred in 33.65% of samples, and Campylobacter spp. positivity was positively associated with Salmonella spp. in poultry and pork. A genomic analysis revealed distinct virulence gene patterns among species, with C. jejuni carrying a broader virulence gene repertoire than C. coli. Conserved pathogenicity islands were detected in Salmonella spp. and L. monocytogenes. cgMLST identified genetically closely related isolates across different stalls and brands, indicating potential cross-contamination in retail environments. Overall, this study integrates multipathogen surveillance with genomic analysis to provide insights into co-contamination dynamics and potential transmission patterns in retail meat environments, thereby extending conventional prevalence-based studies and supporting targeted food safety interventions.