Transmission of AMR <i>Campylobacter</i> and <i>Escherichia Coli</i> During the Processing of Chicken Meat

The emergence and spread of resistance to antimicrobials is of global concern. There is increasing concern that the food chain and food processing environments may significantly contribute to the transmission of antimicrobial resistant bacteria and genes (ARGs), potentially serving as hotspots for the acquisition and spread of antimicrobial resistance (AMR). However, relatively little is known about the role of the food chain in the transmission of AMR bacteria in general, including the transmission and prevalence of AMR bacteria in chicken and chicken products, before retail. The overall aim of this project was to access the impact that processing has on the presence and transfer of antimicrobial resistant Campylobacter species (spp.) and Escherichia coli and associated genes on chicken meat. Our findings showed that while target bacteria like Campylobacter spp. and E. coli were initially present in birds entering the plants, their presence and numbers significantly decreased along the poultry processing line especially following specific procedures such as defeathering and evisceration. AMR testing revealed varying patterns among Campylobacter spp. and E. coli isolates. Campylobacter spp. showed highest resistance to tetracycline (53%) and lowest to erythromycin (7%), while E. coli exhibited highest resistance to ampicillin (80%) and lowest to chloramphenicol (13%). Notably, 7% of Campylobacter spp. and 60% of E. coli isolates were resistant to three or more antimicrobial classes, indicating multidrug resistance (MDR), particularly in E. coli . Whole genome sequencing revealed diverse C. jejuni and E. coli isolates across sampling points. Genomic analysis of parallel samples confirmed reductions in bacterial and associated ARG diversity through the processing chain, suggesting that the hygienic measures implemented during the poultry processing stages can effectively reduce both bacteria and ARGs. Further studies are needed to confirm these results and assess the role of poultry products in spreading AMR/ARGs of concern to human health.