Remnants of antibiotics persist in treated farm waste

Each year, farmers in the US purchase tens of millions of pounds of antibiotics approved for use in cows, pigs, fowl and other livestock. When the animals' manure is repurposed as fertilizer or bedding, traces of the medicines leach into the environment, raising concerns about how agriculture contributes to the rise of antibiotic-resistant bacteria. New research holds troublesome insights with regard to the scope of this problem.