COLUMBUS, Ohio — Just last fall researchers at The Ohio State University detailed the discovery of an antibiotic-resistant gene in a farrowing barn. The fear was that raw meat could carry dangerous germs into the human population.

 

 Dr. Thomas Wittum is chair of the Department of Preventive Veterinary Medicine at OSU, in charge of the team behind the discovery of the antibiotic-resistant gene on the production pig farm, the location and ownership of which has not been disclosed.

 

The gene is called bla IMP-27 and it gives bacteria the ability to resist the effects of a class of antibiotics called carbapenems.

 

Carbapenems, Wittum explained, are considered an antibiotic of last resort, so germs that resist their effects are extremely difficult to kill. “We have national surveillance

in place looking for important antibiotic resistant organisms in farms,” he said. “As part of that surveillance, we detected Carbapenem isolate on a pig farm here in the United States.

 

“That’s a really important type of resistant bacteria because we usually only expect to find those organisms in human hospitals. They’ve never been observed on farms before in this country. The fact that this was present on a farm was really surprising.”

 

The discovery came after investigators collected environmental and fecal samples from the 1,500-sow farrow-to-finish farm over a window of four visits in five months. The resistant bacteria were found growing in agar plates, as a result.

 

“A particularly surprising piece of the study came from the fact that no new livestock were introduced on the farm in the past 50 years, as they have been breeding

their own stock in that time,” Wittum said. Many producers are curious about how such a unique organism found its way to a hog operation.

 

“We’re not really sure,” he said. “We believe it got introduced, probably by the movements of people or animals in some way, but we’re just not sure where it came

from. It originally evolved in a human hospital or some other place and then was introduced onto this farm.”

 

The good news from a study (as reported in a journal of the American Society for Microbiology) was that no meat was contaminated nor humans infected with the

bacteria. Wittum said there was no evidence that pigs carried the gene into the human food supply.

 

“Some of the things that we do on farms to treat sick piglets also can favor the spread

of these resistant organisms,” he noted. “So something we have to change (is) our standard practices, maybe things like rotating antibiotics or other approaches veterinarians can help with, just to be sure that even though we may be treating appropriately, we may still be providing selection pressure that allows these organisms to spread.”

 

Wittum said researchers have been working with veterinarians to learn of their antibiotics use practices and what methods they take to prevent the spread of such resistant organisms. He also said OSU has been part of a nationwide effort to monitor resistance in agriculture.

 

“Research in this area has grown exponentially in recent years,” he added, “and it’s a really important issue for a lot of reasons. There’s definitely been more work looking at the relationship between resistance in animals and humans, because we know that organisms that affect animals affect humans and vice versa.

“We can exchange those organisms whether they’re resistant or not, so we need to understand how those organisms move between animal and human populations.”

 

First, most producers wonder if this so-called “superbug” can be eradicated.

 

“We still don’t know how to control resistant organisms like this once they’re introduced

into a farm,” Wittum said. “Because obviously, the farmer doesn’t want it to be there and we don’t want to have a risk of it being introduced into the food supply. At this point we don’t know how to get rid of it, so that’s one of the things we’d like to figure out.”

Second, producers are fearful the organisms might make their way to farms down the road.

 

“Biosecurity is really important in farms in general, but swine producers in particular really have high levels of biosecurity,” he said. “It’s really important to maintain that strong biosecurity, to help prevent the introduction of pathogens or resistant

organisms like this.

 

“Farmers also need to work closely with their veterinarian to be sure they’re applying antibiotics in the right way and using the right approaches.”

 

Weighing in on the serious situation is Ohio State Veterinarian Dr. Tony Forshey, who is also chair of the National Institute of Animal Agriculture. He said this superbug development is the most recent in a time of vast antibiotic discussion in recent years, from both the producer and consumer perspectives.

 

“For the past six years we’ve held an antibiotic symposium, involving the human medical field as well as the veterinary field and industry,” Forshey explained.

 

“We’ve been talking about how these bugs become antibiotic-resistant and how well they exchange DNA and genetics, and some of these bugs have never seen antibiotics before, yet they carry that resistant gene.

 

“It’s survival of the fittest and they’re doing pretty well at that. We’ve got to come up with alternative ways other than antibiotics to manage disease.”