Superbugs take flight from cattle farms

Being downwind of 50,000 cows is not only bad for your nose; it could also be bad for your health.

Gusts of wind blowing through high-density cattle facilities send veterinary antibiotics and drug-resistant bacteria flying, which could spur difficult-to-treat infections in nearby communities. The finding appears online January 22 in Environmental Health Perspectives.

The study raises more concerns about the overuse of agricultural antibiotics, which account for about 80 percent of all antibiotics used in the United States (SN: 3/8/14, p.5). Such use is known to create drug-resistant bacteria, but little data exist on how these farm-raised superbugs travel and how dangerous they are to humans.

To understand a possible airborne threat, researchers led by environmental toxicologist Philip Smith of Texas Tech University in Lubbock collected breeze-blown particles up- and downwind of 10 high-density cattle facilities around Lubbock. Like many places where these crowded cattle yards exist, the Lubbock area is dry and experiences dust storms.

Compared with upwind samples, downwind air carried higher levels of veterinary antibiotics, probably excreted by animals, dried in dung and launched by rustling cattle. Downwind samples also had more microbes, including those associated with animal excrement and human infections. Probing the genes of those jet-setting microbes, researchers found elevated levels of DNA that make bacteria resistant to antibiotics.