Why did FDA propose the Framework at this time?

"The Framework is the culmination of about 30 years of trying to deal with this issue from a regulatory point of view. It's very difficult to regulate. We know from experience that antibiotics will select for resistant bacteria. There is no question it occurs. We can't regulate that."

Sundlof explains a number of studies in a number of countries have examined how antibiotic resistance in animals might impact human health. Following a rancorous debate about the subtherapeutic animal use of penicillin and tetracycline in the late '70s and early '80s, FDA commissioned several of its own studies in an effort to find a definitive answer. Results were inconclusive.

"Fast-forward to the '90s, and we were going through the process of reviewing one of the newest classes of antimicrobials - fluoroquinolones. At the last stage of the review, we discovered these were the last of a new class of antimicrobials in development.

"The way we've dealt with resistance in the past is to develop new classes of drugs the antimicrobial world hasn't seen yet."

But, with a lag before any new products would come out of the pipeline, Sundlof says the public health community was concerned if fluoroquinolones were approved for animal use, and resistance developed, human medicine would be caught short handed. With strict safeguards, fluoroquinolones were approved for therapeutic treatment in poultry in 1994, then in cattle last year.

"During the approval of fluoroquinolone for cattle, new information came to our attention. We were starting to see resistance develop to Campylobacter, the number one (pathogenic) cause of food poisoning in the U.S. The concern was that fluoroquinolone was the last good drug for treating this disease. FDA felt it couldn't let the problem go unaddressed."

What do we, and what don't we, know about antibiotic use in animals impacting human health?

"We know there are disease-carrying organisms whose primary mode of transmission is food (like Salmonella). We know that bacteria that develop resistance to antimicrobials can be passed between animals and humans. We can track that. We don't know the overall human health impact of that."

Is there enough conclusive evidence to support the Framework at this time?

"One comment we always get is that FDA shouldn't regulate until it has all of the information. We think there is sufficient information, and we can't wait until we have a problem before we start taking regulatory action."

As an example, Sundlof says there was uproar several years ago when FDA regulated the feeding of ruminant protein as a way to safeguard against the introduction of BSE to the U.S. In hindsight, he says getting in ahead of the issue may have saved the U.S. from a major disaster.

If the current Framework is adopted and regulations are developed from it, could it slow the development of new animal antibiotics or restrict the use of existing ones?

"We will do what we can to keep it from happening. I think the industry will find out what we're asking for isn't overly burdensome.

"The reason we've gone through this process is to provide a science-based mechanism that we could feel comfortable with in the approval process. We'll try very hard to keep the regulatory burden as low as we can while protecting the public's health.

"It was our intent to give guidance to the animal health product industry so they could say, 'I know the rules, now I can go forward with the approval application.'

"I'm sure there are a lot of nervous people out there who think this is FDA's way of saying it won't approve any more animal drugs. That's not the intent."

What happens now that the public comment period for the Framework is over?

"We will take into account all comments and make necessary adjustments to the Framework document. Then, we'll propose regulations, if necessary, to implement what's in the document.

"Bacterial resistance is an issue that doesn't go away. By implementing this Framework we hope to have a highly visible program the public can look at and say 'the livestock industry and government worked together and got this issue under control.' "