Environmental reservoirs and transmission pathways of antimicrobial resistance across the pork production continuum

초록

Background Antimicrobial resistance (AMR) is a major One Health challenge linking human, animal, and environmental health, yet the contribution of food production environments to resistance transmission remains poorly understood.Results We conducted a longitudinal shotgun metagenomic study across the pork production continuum from farm to retail to identify environmental AMR reservoirs and transmission pathways of antimicrobial resistance genes (ARGs). Assembly-based, genome-resolved, and source-tracking analyses were integrated to characterize resistomes, microbial communities, and horizontal gene transfer dynamics. ARG abundance and diversity were highest at farms, slaughterhouses, and processing plants and declined toward retail, although clinically relevant resistance determinants persisted throughout processing. Slaughterhouse environments emerged as major contributors to ARG contamination on carcasses, highlighting the importance of environmental exposure at intermediate stages. Resistome structure was closely linked to microbial community composition, with persistent taxa such as Acinetobacter and Pseudomonas serving as key ARG carriers, including genes conferring resistance to tetracycline, aminoglycosides, macrolide-lincosamide-streptogramin, and beta-lactams, multidrug efflux. Co-localization of ARGs with mobile genetic elements demonstrated ongoing potential for horizontal transfer across production stages, and genome-resolved metagenome-assembled genome analyses revealed overlapping resistance and virulence profiles between slaughterhouse- and processing plant-associated bacteria, indicating adaptive persistence within pork production environments.Conclusions Resistome composition across the pork production chain is largely shaped by stage-specific environmental sources, highlighting potential intervention points to mitigate AMR transmission.

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