Abstract
Antimicrobial resistance is an issue of global concern and the quantity of antibiotics used in animal agriculture make it an obvious potential contributor. Subtherapeutic use of antibiotics has likely been the largest contributor to this phenomenon, due to the selection pressure exerted over extended periods of time in the livestock microbiome. The observation of antibiotic resistance in the microbiome (gut, faeces, meat, milk, etc.) of food-producing animals is becoming increasingly common. This paper reviews the literature regarding the contribution of animal agriculture to the global challenge of antimicrobial resistance with a focus on manure, soil and water as reservoirs of resistance. The question of whether reducing or eliminating the use of antibiotics in animal agriculture would be sufficient, effective, or appropriate is addressed, and research priorities are identified.