April 01, 2015

 

 Feedyard dust can include drugs, bacteria

Posted March 18, 2015

Wind-borne dust from Plains states feedyards can include antimicrobials and drug-resistant bacteria, according to a recent study.

Study results published in Environmental Health Perspectives indicate air samples collected downwind from 10 beef cattle production facilities in the southern High Plains contained higher concentrations of antimicrobials, bacteria, and bacteria with genes that convey drug resistance than did samples taken upwind.

“This study clearly demonstrates the potential for antibiotics and bacteria to be transported from beef cattle feedyards into the environment by wind,” the article states. “Thus, it is reasonable to consider how far microbes may be transported from these sources, and if they remain viable after aerial transport.”

The article, “Antibiotics, bacteria, and antibiotic resistance genes: Aerial transport from cattle feed yards via particulate matter,” was published online Jan. 22 in advance of print, which is expected within the next few months.

The researchers took air samples at feedyards with 20,000 to 50,000 cattle, all within 200 miles of Lubbock, Texas.

The article indicates tests on the air samples showed the presence of five veterinary-use antimicrobials. Pathogens found included clostridia and staphylococci. The article also notes that downwind samples had a substantially greater abundance of genes conveying resistance to tetracycline antimicrobials.

Of cattle feeding operations with at least 1,000 cattle, three-quarters are in Colorado, Kansas, Nebraska, Oklahoma, or Texas, according to the article. Those states include a region that has both the highest density of feedlots and the most frequent dust storms in the U.S.

The article also states that dust likely helps distribute microbes throughout the world, and the authors cited previous studies on transcontinental dust movement and presence of microorganisms in the atmosphere. The contents of particulate matter from feedyards in the Plains states provide “significant potential for widespread distribution” of bacteria, antimicrobials, and antimicrobial resistance–conveying genes, according to the authors.