Antibiotic-resistant bacteria discovered in West Texas feedlot

Study raises possible concerns over the transmission of resistant bacteria into the environment and its subsequent interaction with the human population.

Controversy. It's a big word, and it has a lot of meanings: disagreement, dispute, argument, debate, dissension, contention, disputation, altercation, wrangling, quarreling, war of words, hot potato.

Because of its very nature, most people do not particularly like controversy. To be fair, most will agree it is inherent with life.

The great reformer and supporter of temperance, Lyman Beecher, may have best hit the nail on the head firmly when he famously said "No great advance has been made in science, politics or religion without controversy."

A study soon-to-released by a pair of Texas Tech researchers, toxicologist Dr. Phil Smith and microbiologist Dr. Greg Mayer, examines the controversy and risks associated with airborne antibiotic-resistant bacteria caused by overcrowded feedlots. The study raises possible concerns over the transmission of resistant bacteria into the environment and its subsequent interaction with the human population.

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The researchers, who work in Texas Tech's Institute of Environmental and Human Health, are quick to defend their research but say the study is far from over. They warn that additional research is required to gather data, and that could take years to complete. But they confirmed that research so far supports the possibility that antibiotic use in feedlots over time can create a cloud of superbugs capable of airborne transmission and subject to movement by the wind.

So the controversy begins.

No axe to grind

Smith and Clark say they have no axe to grind and are not out to take one side or the other concerning the issue of antibiotic use in the cattle industry. Their concerns and interests are in the evolution of bacteria in the environment—what causes it to spread, what is the best way to manage and control it, and what are the implications for human health.

The study has largely been focused on large feedlots in the Texas Panhandle and across the High Plains. A series of air monitoring tests near feedlots determined a number of bacterial species and genetic sequences that code for antibiotic resistance around heavily populated feedyards. The bacteria were discovered riding on microscopic air particulates above cattle yards.

Such conditions make it possible, researchers say, for strong winds, like those experienced in the plains, to drive these particulates to more populated urban centers where superbugs could mingle with human hosts.

The research is not setting well with cattle producers and a number of veterinarians who defend the use of antibiotics in cattle. They tend to believe that the risks of antibiotic superbugs and their spread to the general population is extremely over-rated and most agree that the benefits of antibiotic use is both beneficial to animals and the public and argue that careful and calculated care is taken in the administration of antibiotics.

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 told reporters recently.

But scientists have known that humans can contract antibiotic-resistant bacteria by consuming contaminated meat or water, and statistics support the spread of superbugs in the human population. The Center for Disease Control in Atlanta reports about 23,000 people die from antibiotic-resistant bacteria each year and the number is growing.

Next steps

Smith says the concern of the study is now focused on finding out if humans could be exposed to so-called super bugs or super bacteria traveling through the air.

The researchers collected dust samples upwind and downwind from 10 commercial cattle feed yards over a six month period. Smith says they discovered a large number of bacteria-attracting particulates upwind of these feedlots compared to the number collected at downwind locations. They conclude that these contaminated particulates must be riding prevailing winds and could pose a risk of settling in an area where they might pass their resistant genes to local bacteria, further exacerbating the problem.

"That doesn't mean that humans are necessarily at risk, so our next step is to determine how far these particulates may move and what happens when they settle out," Smith said.

Despite what he has learned from his research, Smith doesn't fault farmers and ranchers for the way they raise cattle and supply the nation with food.

"I love a great steak," Smith said. "I love a hamburger and I know that a lot of people do. We all want good, healthy food choices, but we also want good prices. It's important to produce a good, healthy product, which our beef producers do, and do it in a manner that is economical for a large population."

He hopes his findings will help raise awareness of what could be a growing issue and that it will foster good stewardship.

"We just want to produce information that is useful for wise decision-making," Smith said.

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