Persistence of erythromycin resistance gene erm(B) in cattle feedlot pens over time

Antibiotic resistance in food animals has become an important issue for public health safety. The genes that code antibiotic resistance often enter the feedlot environment via feces and have the potential to be transferred through agroecosystems and into the food chain, either directly in their original bacterial host or via horizontal gene transfer. The objective of this study was to determine the distribution of erythromycin resistance genes associated with beef cattle excretions and ascertain whether these genes are enriched in areas of feedlot pens with high deposition of fecal material over time. The spatial distribution of manure accumulation was determined using georeferenced electromagnetic induction (EMI) readings at two times and EMI directed soil sampling. Feedlot surface samples from high- and low-manure accumulation zones were compared. The data indicated that 14 months of manure accumulation did not result in an increase in erm(B) positive feedlot soils, and the distribution of erm(B) genes was not correlated with areas of high manure deposition within the pens.