A group of Texas Tech University researchers have found evidence of aerial transmission of antibiotic resistance while studying dust in the air near Southern Plains cattle feedlots.
In addition to evidence of antibiotics, the researchers identified feedlot-derived bacteria and DNA sequences that encode for antibiotic resistance.
The study was published online in the National Institutes of Environmental Science's peer-reviewed journal, Environmental Health Perspectives. The research was funded through a grant from Texas Tech's College of Arts and Sciences.
It is the first study documenting aerial transmission of antibiotic resistance from an open-air farm setting, the University said.
Phil Smith, an associate professor of terrestrial ecotoxicology at the Institute of Environmental and Human Health at Texas Tech said the study identifies a pathway by which antibiotic-resistant bacteria could travel to get to humans.
Smith said scientists collected air samples upwind and downwind of each feedlot. After analysis, they found greater amounts of bacteria, antibiotics and DNA sequences responsible for antibiotic resistance downwind of the feedlots compared to upwind, which helped scientists determine the source of the materials they found.
Because the antibiotics are present on the particulate matter with bacteria, the selective pressure for bacteria to retain their resistance remains during their flight, said Greg Mayer, an associate professor of molecular toxicology at the institute.
With wind blowing regularly on the Southern High Plains, the antibiotics and bacteria can travel on the dust and particulate matter far from the original starting point at the feedlot. They could potentially travel hundreds of miles to cities and towns.
"I think implications for the spread of some feedlot-derived, antibiotic-resistant bacteria into urban areas is paramount to the research," Mayer said. "Now, we haven't yet taken samples from an urban area to determine whether bacteria from that particulate matter originated from feedlots or whether it still has antibiotic resistant bacteria on it. However, this study is proof of the principle that antibiotic-resistant bacteria could plausibly travel through the air.
"Further studies are now needed to show where the particulate matter is traveling and what is happening to its passengers when it gets there."
Source: Texas Tech