Contamination Profiles of Pathogens, Virulence Factors, and Antibiotic Resistance Genes in Four Categories of Commercial Braised Meat Products from Changsha, Central China

Abstract

Antimicrobial resistance (AMR) poses a critical global public health threat, and ready-to-eat (RTE) braised meat products represent a key vehicle for the foodborne spread of pathogens, antibiotic resistance genes (ARGs), and virulence factors (VFs). However, systematic data on the tripartite "pathogen-VF-ARG" contamination landscape of braised meat products in central China remain limited. In this study, we used shotgun metagenomic sequencing to characterize microbial contamination profiles in 20 commercial braised meat samples (5 beef, 5 pork, 5 chicken, 5 duck) collected from Changsha, China. Across all samples, we identified 897 microbial species, 1699 ARG subtypes, and 427 VF subtypes, with highly significant category-specific differences in microbial diversity, pathogen distribution, and functional gene profiles (P<0.01). Braised pork was classified as a high-risk category, with the highest microbial diversity, pathogen abundance (18.72±6.34%), and ARG/VF contamination levels. Notably, World Health Organization (WHO) critical-priority ARGs (blaKPC, blaNDM, mcr-1), as defined in the WHO Critically Important Antimicrobials (CIA) for Human Medicine List, were detected in 100% of braised pork samples. Braised beef and chicken were categorized as medium-risk, with unique category-specific contamination signatures, while braised duck presented the lowest risk, with negligible detection of high-priority pathogens and critical ARGs. Significant positive co-occurrence was observed between dominant pathogens and their corresponding ARGs/VFs (r>0.7, P<0.01), and we proposed a preliminary three-level microbial risk classification framework for braised meat products based on these findings. Our results complement prior regional food safety studies published in the Chiang Mai J. Sci. and expand the global knowledge base of foodborne AMR in Asian RTE meat products.