Cow manure harbors diverse new antibiotic resistance genes

Manure from dairy cows, which is commonly used as a farm soil fertilizer, contains a surprising number of newly identified antibiotic resistance genes from the cows' gut bacteria. The findings, reported in mBio® the online open-access journal of the American Society for Microbiology, hints that cow manure is a potential source of new types of antibiotic resistance genes that transfer to bacteria in the soils where food is grown.

Thousands of antibiotic resistance (AR) genes have already been identified, but the vast majority of them don't pose a problem when found in harmless bacteria. The real worry is when these genes appear in the types of pathogenic bacteria that cause food-borne illnesses or hospital infections.