Antibiotics are ubiquitous in our society because of their medical and agricultural uses, yet we lack a fundamental understanding of the ecological impacts of these naturally occurring compounds. Additionally, antibiotic resistance has been deemed a global health crisis by the United Nations, yet our understanding of the ecology and biogeography of antibiotic resistance remains limited. In this study, we collected soil samples from 220 sites across the United States and performed a novel targeted gene capture technique that allowed us to document the abundance and diversity of > 78,000 antibiotic resistant genes. We then compared levels of antibiotic resistance to a variety of soil properties and environmental characteristics, providing key insight into what factors may contribute to environmental antibiotic resistance.
Results/Conclusions
We found that antibiotic resistance varies dramatically across geographical space. We also found that environmental characteristics like land-use history, nutrient availability and urbanization all influence the diversity and abundance of antibiotic resistance. While the biogeography of soil microbial communities and functional genes have been well documented, the biogeography of the soil resistome has not. This work provides one of the first comprehensive maps of environmental resistance. It also provides key insight into which environmental factors may shape the resistome, and therefore, how we can manage our soils to limit antibiotic resistance levels.