Intensive Farming May Yield a Bumper Crop of Drug-Resistant Pathogens

When people imagine the front line of antibiotic resistance, they may see a hospital where antibiotics are overprescribed, or a feed lot where cattle are pumped full of these drugs. They probably won’t picture a cornfield. But a new study suggests that crop fields may be an important battleground for fighting antibiotic resistance. And the way we farm will decide who wins.

The new study, published in Proceedings of the National Academy of Sciences, found that high-intensity farming, typical of the U.S. Corn Belt, produced soil microbiomes that were more likely to transmit antibiotic-resistant pathogens to humans, compared to lower-intensity farming methods. In other words, modern farming may contribute to drug-resistant infections, which kill up to 4.7 million people per year, worldwide.

To find out how farming methods affect this risk, researchers compared the soil microbiomes from four widely used farming schemes: high-intensity corn cropping with heavy tilling, synthetic fertilizers, and non-antibiotic biocides to combat pathogenic fungi; two medium-intensity cropping schemes, with reduced biocides and tilling, and use of cow manure to reduce or eliminate synthetic fertilizers; and low-intensity grazing rotated with no-till cover crops, with only intermittent biocides, manure, or synthetic fertilizers.