Residential proximity to intensive animal agriculture associates with increased prevalence of antimicrobial resistance in homes

BACKGROUND: Antimicrobial resistance (AMR), a global public health threat, affects rural communities disproportionately due to their unique regional exposures, including proximity to animal feeding operations (AFOs), a source of AMR genes. OBJECTIVE: We evaluated residential proximity to AFOs and the presence of AMR genes in the home dust resistome, the collection of antimicrobial resistant genes within a microbial community. METHODS: We conducted metagenomic sequencing of 534 bedroom dust samples to characterize the resistome for a subset of homes of Iowa participants in the US Agricultural Health Study. We examined the association between the presence of AMR genes in dust samples and the total number of AFOs and distance-weighted number of livestock animal units (AUs) within 2, 5, and 10 km of participant homes, using data from the Iowa Department of Natural Resources. RESULTS: Homes that were closer to a greater number of AFOs and AUs had increased odds of the presence of AMR genes in the dust, including genes resistant to multiple classes of antimicrobials. SIGNIFICANCE: We found that AFOs were positively related to the composition of the indoor home dust resistome, which may serve as a potential environmental reservoir of antimicrobial resistance with implications for the health of household occupants. IMPACT: This study is the first to detect a positive association between the presence of antimicrobial resistance (AMR) genes in the indoor home dust resistome and residential proximity to animal feeding operations (AFOs), a known reservoir and possible source of AMR in rural communities. Our results indicate that both distance and density were important components of AFO-related AMR risk in rural residential environments. Overall, this suggests that environmental exposures can shape the indoor home dust resistome, which may have implications for the health of inhabitants and increase the risk of AMR infections.