Impact of swine and beef cattle manure treatment on the resistome of soil and water effluent from artificially drained croplan

Evaluation of the environmental and potential clinical impacts of practices used by indus-tries that consume large amounts of antibiotics is critical in mitigating the spread of antimicrobial resistance. Using soil columns to simulate field application and subsequent rain events, we identi-fied important differences in the dynamics of antimicrobial resistance gene transfer and enrichment over time in the soil and water of artificially drained cropland treated with swine or beef cattle manure. Using a targeted PCR-based approach, we were able to track resistance genes from source manures and determine their persistence in the soil column and abundance in effluent water over time. The source manures had distinct microbial community and resistance gene profiles, and these differences were also reflected in the soil columns after manure application. ARGs were only signif-icantly enriched in effluent samples following the first rain event (day 11) for both soil types com-pared to the control columns, illustrating the high background level of resistance present in the control soils chosen. The characteristics observed following application of each manure type, par-ticularly the unique temporal dynamics of ARG transfer observed between soil and water, can be used to inform potential mitigation strategies in the future.