The debate over the subtherapeutic use of antibiotics in animal agriculture brought veterinarians, public health officials, scientists, and industry representatives to Congress last week for a hearing, the third in a series held by the House Energy and Commerce Subcommittee on Health on growing antibiotic resistance.

The hearing comes just a few weeks after the U.S. Food and Drug Administration (FDA) issued a draft guidance “intended to help reduce the development of resistance to medically important antimicrobial drugs,” which are widely used in food animal production to ward off disease and promote growth.

In the meeting, Rep. Henry Waxman (D-CA) called the draft guidance “a good first step,” but stressed that more could be done to combat the problem.

“We must do more to tackle this piece of antibiotic resistance puzzle. And we must do so as part of a comprehensive strategy designed to safeguard the vitally important public health tool that is our antibiotics. It is critical that we encourage the development of new drugs,” he said. “But it is also essential to preserve the antibiotics we already have. That means we must move expeditiously to slow the advancement of antibiotic resistance in both humans and animals.”

Experts from the U.S. Department of Agriculture (USDA), the Centers for Disease Control and Prevention (CDC), and FDA discussed the link between antibiotic resistance in humans to the use of medically important antibiotics in animals.

“USDA believes that it is likely that the use of antibiotics in animal agriculture does lead to some cases of antibacterial resistance among humans and in the animals themselves, and it is important that these medically important antibiotics be used judiciously,” Dr. John Clifford, the USDA Animal and Plant Health Inspection Service deputy administrator for veterinary services, told the committee last Wednesday.

“We need to work together to conduct research and develop new therapies that protect and preserve animal health, without increasing the risk of resistance to medically important antibiotics,” said Clifford in his prepared statement, adding that the agency must partner with farmers and producers, in addition to federal agencies, to facilitate the judicious use of antibiotics “in ways that are feasible to farmers and ranchers.”

Dr. Thomas Frieden, director of CDC, submitted responses to questions in time for the committee hearing, clarifying the agency’s position on the issue. Using much stronger language than in previous testimony, Frieden said there is “strong scientific evidence of a link between antibiotic use in food animals and antibiotic resistance in humans.”

Representing FDA at the hearing, Joshua Sharfstein, principal deputy commissioner of the agency, said the agencies were having “good discussion” on antimicrobial resistance, as it relates to food safety, in the President’s Food Safety Working Group.

Sharfstein also pushed back against criticism of FDA’s draft guidance, telling lawmakers the document was based on a “mountain of scientific evidence.”

The American Veterinary Medical Association (AVMA) and the Animal Health Institute, a trade group representing veterinary pharmaceutical companies, questioned the science linking growing resistance to agricultural use, called for more research, and described antimicrobials as a critical tool for food safety and animal health.

According to Dr. Christine Hoang, assistant director of the scientific activities division at AVMA, “a direct epidemiological investigation still cannot be completed.” Hoang cautioned lawmakers about the potential of unintended consequences from any “preemptive” ban on antimicrobials.

“Simple solutions may not solve such complex problems,” said Hoang, in her prepared statement. “Inappropriate reactions could have unknown and unintended consequences that negatively affect animal health and welfare, and ultimately, could create other public health risks, such as increased foodborne illness.”

Dr. Richard Carnevale, vice president of scientific, regulatory and international affairs at the Animal Health Institute expressed similar concerns.

“Research shows that the first link in the chain of producing meat, milk, and eggs is keeping animals free from disease,” said Carnevale in his prepared testimony, adding that the industry is committed to working with FDA to address concerns about antibiotics use in food animal production.     

The FDA is inviting comments on the draft guidance, The Judicious Use of Medically Important Antimicrobial Drugs in Food-Producing Animals (pdf). See the Federal Register notice (pdf) for more information.

The agency is accepting comments on a rolling basis, but recommends submitting before August 30 for comments to be considered in the next draft.