Macrolide and Tetracycline Resistance Genes in Tile-Drainage and Stream Water in an Agricultural Watershed.

The contribution of antibiotic use in agriculture to the emergence of antibiotic-resistant pathogens affecting human health is currently controversial. Previous studies have shown that manure contains high concentrations of these genes. The transport and fate of genes coding for antibiotic resistance in streams has been less frequently investigated.  We used qPCR to measure the occurrence of genes coding for resistance to macrolide and tetracycline antibiotics in water from the South Fork of the Iowa River. Concentrations generally ranged from non-detectable to greater than 1000 copies/mL of river water.