Using microbial transmission potential networks to identify and mitigate transmission of antimicrobial resistant bacteria among livestock and wild birds

Antimicrobial resistance (AMR) in the food chain threatens both human health and the stability of livestock-based agriculture. Annual livestock production losses due to AMR are projected up to 10%, while cumulative global GDP losses for 2025-2050 could reach US$1 trillion. For farmers, AMR increases costs and reduces productivity by prolonging illness in livestock, raising veterinary expenses, and elevating morbidity and mortality rates. Wild birds have been implicated in spread of AMR among farms and may serve as reservoirs that facilitate continued emergence of novel AMR bacteria in farms. Our goals are to 1) identify reservoirs of AMR around livestock farms, 2) measure the extent to which wild birds transmit AMR within and among farms, and 3) identify factors contributing to AMR transmission among livestock and wild birds. We will sample the common bacterium E. coli from wild birds and livestock at 10 farms. To measure bacterial transmission among hosts, we will sequence E. coli isolates to identify sharing of bacterial genes, with a focus on genes associated with AMR. We will analyze networks of shared genes to identify farm and environmental factors associated with increased bacterial sharing and AMR transmission. By identifying factors contributing to increased prevalence and transmission of AMR within and among farms, this work will address the program area priorities of 1) identifying key AMR risks at a critical control point within the food chain, 2) identifying factors that impact AMR development, and 3) determining improved management practices in antibiotic stewardship and dispense this information to stakeholders.