In some cases, drug-resistant DNA was found to be 4,000 percent more abundant in air samples collected downwind of feed lots. File Photo by Jim Bryant/UPI | License Photo
LUBBOCK, Texas, April 1 (UPI) -- Researchers in Texas say they've located a new route by which drug-resistant bacteria can travel and spread to humans -- the air.
Antibiotics and antibiotic-resistant bacteria are taking to the air near Texas cattle ranches. And according to a new study, the bacteria are capable of traveling lengthy distances.
As part of they study, scientists at Texas Tech University analyzed air samples from 10 cattle yards near Lubbock, Texas. All of the samples tested positive for the antibiotic oxytetracycline. Six of the samples also tested positive for tetracycline and chlortetracycline.
In addition to antibiotics, the researchers also found microbial communities with high levels of antibiotic-resistant genes. In some cases, the drug-resistant DNA was found to be 4,000 percent more abundant in air samples collected downwind of feedlots -- as opposed to upwind.
The drugs and bacteria don't take to the air on their own, but travel on dust and particulates picked up by the wind around cattle feedlots, which often feature thousands of cattle packed into tight quarters.
"People living in the vicinity of feed yards often complain about excessive dust, and airborne microorganisms and byproducts from feed yards are considered potential human health threats," researchers wrote in their new paper, published recently in the journal Environmental Health Perspectives.
"This is the first test to open our eyes to the fact that we could be breathing these things," study author Phil Smith, an environmental toxicologist at Texas Tech, told the Texas Tribune.
While most of the antibiotics given the cattle are different from the drugs used to treat infections in humans, their presence can enable bacteria to adopt resistance to entire classes of antibiotic drugs. In recent years, healthcare professionals have voiced public concern over the proliferation of drug-resistant infections.
Not everyone is convinced the study is cause for alarm.
Dr. Sam Ives, a veterinarian working with the Texas Cattle Feeders Association, said antibiotic use in the industry is "judicious."
"If I truly thought that the usage of these products was putting anyone at danger, I wouldn't be using them," Ives said, adding that the research overstates the risk of superbugs and bacteria to human health.