Impacts of antibiotic use in agriculture: what are the benefits and risks?

Antibiotic drugs provide clear benefits for food animal health and welfare, while simultaneously providing clear risks due to enrichment of resistant microorganisms. There is no consensus, however, on how to evaluate benefits and risks of antibiotic use in agriculture, or the impact on public health. Recent soil resistome work emphasizes the importance of environmental reservoirs of antibiotic resistance (AR), and provides a starting point for distinguishing AR that can be impacted by agricultural practices from AR naturally present in a system. Manure is the primary vehicle introducing antibiotic drugs, AR bacteria and AR genes from animals into the environment. Manure management, therefore, impacts the transfer of AR from agricultural to human clinical settings via soil, water, and food. Ongoing research on the ecology of naturally occurring and anthropogenically derived AR in agroecosystems is necessary to adequately quantify the benefits and risks associated with use of antibiotics in food animals.