Wikimedia, Brian StansberrySoil microbes exposed to antibiotics over a long period evolve the ability to detoxify the compounds, and may even derive nutritional benefit in the process, according to a report out last week (December 6) in the Journal of Environmental Quality.
Antibiotics administered to promote the growth and health of livestock find their way into agricultural soils through the manure of the treated animals, which is used as fertilizer. To see how long-term exposure to these medicines affect bacteria in the soil, researchers set up an experiment more than a decade ago in which plots of land were dosed every year with a mixture of three common veterinary antibiotics—sulfamethazine, tylosin, and chlortetracycline.
Ten years on, the team found that sulfamethazine and tylosin were degraded much more rapidly in soils with a history of antibiotic exposure than in untreated soils, suggesting that antibiotic-degrading microbes are selected for over time. They also found that residues of sulfamethazine were quickly mineralized to carbon dioxide in exposed soils, but not ...
