1. The objective of our study was to determine the effect of liquid swine manure application rate and timing on soil leaching of ARB and their associated genes.
2. The general approach of this proposed study was to pass swine lagoon effluent known to contain ARB through soil at two manure application rates and three time intervals between manure application and first rainfall-induced leaching event using laboratory soil columns. We also conducted similar experiments using swine lagoon effluent spiked with two antibiotic resistant bacteria: E. coli and Salmonella. Time intervals between swine manure application and rainfall application were 1, 7, or 21 days. Transport and attachment behavior of the ARB and associated genes were evaluated in custom-made polycarbonate cylindrical columns packed with soil. Each treatment was conducted in triplicate using a full factorial design. Effluent from columns were plated onto tetracycline-, erythromycin-, and ampicillin-amended Reasoner’s 2 Agar (R2A) to determine the extent of transport of resistant bacteria that exhibit resistance to these antimicrobials. For the experiments using spiked swine lagoon effluent we used organism-specific media with the appropriate antibiotics added.