Long-term effects of manure from cattle administered antibiotics on soil microbial communities and ARG abundances

Antibiotic usage has continuously increased since their discovery and the resulting microbial resistance to antibiotics has been a growing concern. In agroecosystems, treated livestock have the potential to spread antibiotic compounds, resistant bacteria, and antibiotic resistance genes (ARGs) to soil through manure. Although environmental transmission of antibiotic resistance is a major human health concern, few studies have looked at long-term effects of antibiotics from livestock on soil microbial communities. We examined the impacts of three years of repeated additions of manure from cattle under different antibiotic treatments on microbial community structure. Manure was added monthly. Soil samples were collected after 8, 20, and 32 months of manure applications to examine long term impacts on bacterial and fungal commuities.