Mar 29

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Various groups and individuals representing animal agriculture and the animal health industries feel FDA has failed to substantiate, on a scientific basis, a human health hazard resulting from fluoroquinolone use in poultry. In written comments filed with the agency, industry has told FDA it believes its action was based on unfounded assumptions, selective data and inappropriate risk assessments.

The issue of antibiotic resistance, including that being associated with fluoroquinolone use in poultry, is definitely a sensitive and far-reaching matter. It is an issue that concerns those producing meat products as well as those consuming them. Nevertheless, the points industry raises should not be ignored or simply brushed aside, for if they hold true, FDA could actually be putting more consumers at risk by banning fluoroquinolone use in poultry then by allowing the antimicrobial to remain on the market. There’s no question poultry producers and the birds they raise will suffer from the product’s removal.

Much of the difference of opinion that exists between FDA and industry surrounds the assessment of risk in regard to fluoroquinolone use in chickens and fluoroquinolone-resistant campylobacter in humans. Both sides believe the use of antibiotics in humans or animals could eventually result in the development of resistance or the creation of conditions that allow the expression and recognition of resistance genes that existed prior to antibiotic use. The unknown is the degree to which this has already occurred with campylobacter in poultry and whether an unacceptable risk is created when compared with the risks resulting from the withdrawal of therapeutic uses of enrofloxacin in poultry. As pointed out by the American Veterinary Medical Assn. (AVMA) and others, these risks include reduced animal health and welfare as well as a less economical and wholesome food supply.

Also being called into question is the National Antimicrobial Resistance Monitoring System (NARMS) classification of campylobacter isolates from chickens classified as fluoroquinolone “resistant” and studies reporting “resistant” campylobacter in retail samples of chicken. AVMA and others have pointed out that the scientific data do not clearly demonstrate the “resistant” campylobacter are truly resistant in terms of clinical outcomes. Seeing that neither the laboratory methods used to test for susceptibility of the campylobacter nor the interpretations of resistance were validated by the National Committee for Laboratory Standards or FDA’s Center for Drug Evaluation & Research, industry makes a very good point. From a scientific standpoint, it just doesn’t make sense for the breakpoint used to classify campylobacter as resistant to not be directly correlated with clinical effectiveness. Doing so brings to question whether the “resistant” campylobacter is in fact resistant, particularly when one considers th at several studies have shown “resistant” campylobacter to respond to treatment with fluoroquinolones.

Like with the NARMS data, FDA’s risk assessment also does not compare well with data from the Centers for Disease Control & Prevention’s (CDC) FoodNet, which is interesting, seeing that human illness data used in the risk assessment are based on CDC’s FoodNet data. Substantial improvements in food safety between 1998 and 1999 appear substantially understated by FDA’s risk assessment model, industry has said.

Another area of concern is directly related to FDA’s premise that fluoroquinolone-resistant campylobacter is transferred to humans and is a significant cause of infections in humans. Of particular interest is the influence of international travel by U.S. consumers and how that corresponds to campylobacter incidents. According to industry, data exist that show the greatest association with human campylobacter infections is, in fact, human travel, followed distantly by drinking raw milk, eating of meat cooked outside the home, having contact with farm animals, living on or visiting a farm, contact with puppies, eating undercooked poultry and eating raw seafood.

In the interest of public health, FDA should focus on determining where the real risks lie and then concentrate its efforts on those factors.

Making such determinations are especially important considering the National Chicken Council’s (NCC) claim that the risk to human health may actually be increased with the withdrawal of fluoroquinolones from poultry. According to NCC, the loss of enrofloxacin to the chicken industry — in addition to resulting in the unnecessary suffering of millions of birds, including death — would result in a significant increase in the risk of poultry products purchased by consumers being contaminated with enteric foodborne pathogens. If public safety is truly the motivating factor for FDA in its action against fluoroquinolone use in poultry, then it only makes sense that the agency would be concerned about any potential correlation between enrofloxacin used in chickens and intestinal wall strength.

Considering the unanswered questions and valid concerns that exist with the proposed withdrawal of enrofloxacin use from poultry, FDA has little choice but to grant an opportunity of hearing to Bayer sponsor company of enrofloxacin, and give the company the opportunity to present its case.

If, following re-evaluation, the science shows fluoroquinolone use in poultry presents a human health risk, FDA has an obligation to prohibit the antimicrobial’s use by poultry integrators.

FDA owes it to consumers, as well as the poultry and animal health industries, to thoroughly examine all scientific data and alternative risk assessment models submitted in response to its proposal to remove enrofloxacin from the poultry market. Only by doing so will the agency be able to say with confidence that the action it took was based on sound scientific principles and not simply perceived risk.


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