FDA continues to deliberate actions to control antimicrobial resistance

FDA continues to deliberate actions to control antimicrobial resistance

Feb 01, 2003

Washington-The Food and Drug Adminis-tration (FDA) is still gathering input about its proposal to curb antibiotic drug resistance.

FDA's Center for Veterinary Medicine asked both the American Veterinary Medical Association (AVMA) and the Animal Health Institute (AHI) to deliver their arguments on a proposed risk-management system to evaluate new and existing animal antibiotics. Both associations have voiced concerns over the proposal.

Dr. Michael Apley, of Iowa State University and vice chair of AVMA's steering committee on antimicrobial resistance, delivered the AVMA statement to FDA's Anti-Infective Drugs Advisory Committee meeting Jan. 8-9. Dr. Richard Carnevale spoke on behalf of AHI, an industry organization that represents animal health manufacturers.

The January meeting came in the wake of two key events in late 2002.

* Consumer Reports published results of a study citing extensive contamination of samples from store-bought chicken with campylobacter and Salmonella, including resistant strains. Outcome: Industry reaction is that it's no knockout for limiting antibiotic use in poultry, but it may erode consumer confidence about the safety of the food supply.

* Industry groups submitted comments to FDA about its plan to evaluate the safety of antimicrobial new animal drugs with regard to their microbiological effects on bacteria of human health concern. Outcome: AVMA is very concerned that the result will be a worsening veterinary drug shortage, and possible restrictions on extra-label use of antibiotics for veterinarians.

The latest FDA meeting was to gather more scientific opinion on the subject in order to postulate its final guidance document, which will spell out how antibiotics are approved in the future. Veterinary officials won't even hazard a guess on when the final guidelines will be released. FDA's draft guidance was in the works for about three and a half years.

Thumbs down on poultry

It all comes on the heels of a Consumer Reports study that is down on poultry production. But it's not all about chickens. The issues are about protecting animal health, preserving veterinarians' clinical judgment with extra-label use and maintaining an arsenal of FDA-approved veterinary antibiotics while not unleashing resistant strains of bacteria that could make people sick.

Ron Phillips, AHI's vice president of legislative affairs, says of the Consumer Reports study, "There is a grand war being fought here, and the issue is food safety."

The Center for Science in the Public Interest (CSPI), a consumer advocacy group that is calling on FDA to ban certain antibiotics from production animal medicine, was quick to issue a statement following publication of the Consumer Reports study. CSPI states, "Consumer Reports' findings meant that food poisoning illnesses from chicken are likely to be more serious, causing more doctor visits, longer hospitalizations, and more deaths because of antibiotic resistance. It's good news that there is less bacteria on chicken generally, but it is very bad news that more of that bacteria is resistant to the kinds of antibiotics used to treat serious food poisoning."

Results showed that 42 percent of samples harbored campylobacter, down from 63 percent in 1997. For Salmonella, 12 percent tested positive, down from 16 percent in 1997.

The testing

But while the Consumer Reports study showed an increase in resistant forms of bacteria, the data on poultry isn't as bleak as it looks, says Vogel.

In fact, the highest percentage of resistance was found in campylobacter to tetracycline, and this antibiotic is not used to treat campylobacter or Salmonella infections. The most common choice for physicians is ciprofloxacin and the report showed no resistance in Salmonella. The report did show resistance to campylobacter by 26 percent of samples, which was higher than data from the government's National Antimicrobial Resistance Monitoring System (NARMS).

Vogel adds, "This is kind of questionable, and it makes you wonder about the sampling and testing methodologies done by Consumer Reports and how comparable that really is to other larger sampling programs like NARMS."

Phillips adds, "This little media event that was generated by Consumer Reports and their activist friends is not going to have an impact. It is more of an effort to lead the public down a road that doesn't have basis in fact."

Recommendations made by Consumer Reports were to require companies to monitor data on the use of antibiotics in food animals and ban the subtherapeutic uses of "medically important drugs in poultry and other livestock."

Vogel says, "I wish they would have explained more clearly which antibiotics are used to treat Salmonella and campylobacter infections in humans rather than just testing for a number of them and inferring that there is a bigger problem than there really is."

Even though the study received national media attention after its publication, veterinary officials don't believe that it will impact the new rules FDA is currently mulling over.

Making comments

Last December, industry groups submitted comments to the agency for review on its proposed plan to prolong the effectiveness of antibiotics.

AVMA's position pointed out the following areas of concern:

* This proposed risk analysis did not include an important component - risk communication. In other words, what is the level of risk the public is willing to accept?

* Simply limiting veterinary antibiotic use may jeopardize animal health and welfare without providing a benefit to human health.

* FDA needs to re-evaluate how it measures the importance of antibiotics to human medicine.

* Limiting extra-label use of drugs was cited as a risk management tool. AVMA cautions against an overly conservative approach that would put additional drug use restrictions on veterinarians.

* The potential withdrawal of approved antibiotics would only further the veterinary drug shortage.

Vogel says that AVMA is very concerned that FDA will push to decrease use of antibiotics without a risk-benefit analysis. Vogel adds this approach alone just won't work. And that sentiment has been espoused by FDA's Deputy Commissioner Dr. Lester M. Crawford, who says FDA's strategy is to control or reduce antimicrobial resistance while still treating animals.

AVMA states, "Therefore, additional requirements for new animal drug approvals, and retention of current approvals, must be applied prudently to balance the needs of public health, and animal health and welfare."

Vogel adds that the antibiotic resistance issue is not isolated to just food animal medicine. Beginning last month, the FDA is making available the most recent AVMA documents on judicious use of antimicrobials for beef and dairy producers. All in all, AVMA has drafted seven different judicious use principles for all the major species, including companion animals.