Despite big talk, the agency did not confront the structural problem of antibiotic use in farm animals, which means the public health dangers of meat production remain.



"FDA takes steps to protect public health," blared the Food and Drug Administration (FDA) press release announcing the release of voluntary guidance documents on Wednesday. The documents outline how antibiotics should--and should not--be used in food animal production to slow the development of antibiotic-resistant bacteria. The agency has trumpeted the documents as the beginning of the end of the misuse of these drugs on farms.

The FDA missed the point, however. While the documents call for ending the use of antibiotics to make animals grow faster, they endorse the continued use of these drugs to compensate for overcrowded and unsanitary conditions and prevent disease at the industrial operations that produce most food animals in this country. The preventive or "prophylactic" use of antibiotics is similar to their use for growth promotion, involving comparable low doses that are equally culpable in the development of antibiotic resistance.

The FDA calls preventive use "necessary to assure animal health." Left unaddressed is what makes this use "necessary." The industrial model of food animal production increases animals' exposure to bacterial pathogens and weakens the animals' immune system through overcrowding and the suppression of normal animal behaviors, leaving them susceptible to infections without the continuous administration of low doses of antibiotics. Rather than ban preventive use of antibiotics to require the industry to raise animals in a manner that assures both public and animal health, the guidance document accommodates an industry that undermines both.

The Low-Hanging Fruit

The guidance documents spell out two principles for the "judicious use" of antibiotics in food animal production. First, antibiotics should only be used when "necessary to assure animal health." This means the treatment, control, and prevention of disease, but not growth promotion, according to the FDA. Second, antibiotics should be available only when prescribed by a veterinarian and not sold over the counter.

The FDA had previously approved the use of several antibiotics for growth promotion. Rather than forcibly withdraw these approvals--a move that many drug companies would oppose--the agency believes it can persuade drug companies to voluntarily change existing approvals to comply with the guidance documents. The Animal Health Institute, an industry lobby group, has said it supports the guidances, as have several pharmaceutical executives.

We can expect the FDA and drug companies to revoke existing approvals for growth promotion over the next several years. Likewise, the agency and the drug industry will gradually end the sale of antibiotics over the counter.

The effect of these actions on the use of antibiotics will depend in part on whether or not the food animal industry complies with the changes. There is good reason to doubt the food animal industry will comply. A recent study by the Johns Hopkins Center for a Livable Future, which I direct, strongly suggests that the poultry industry has continued to use a class of antibiotics known as fluoroquinolones, despite an FDA ban on the use of these drugs in chickens and turkeys. These findings raise an important question: how can we expect the industry to comply with voluntary guidance documents if it does not follow existing law?

Even if the food animal industry complies, however, the misuse of antibiotics will continue, because the guidance documents endorse the use of these drugs for disease prevention. Like growth promotion, this means feeding small quantities of antibiotics to food animals throughout their lives--a practice that has been shown time and again to select for antibiotic resistance. It is quite different from the preventive use of antibiotics in human medicine, which is relatively rare and involves the use of full doses for short durations.

Although growth promotion may be phased out, the drug and food animal industries will not give up the use of antibiotics for disease prevention so easily, as preventive use of these drugs is essential to the industrial model of food animal production.

The Industrial Model

The second half of the twentieth century witnessed the transformation of animal agriculture. Beginning in the 1940s, small independent farms were subsumed by industrial operations controlled by a small handful of large corporations. Since the 1950s, the number of food animals produced in the United States has doubled, while the number of production sites has declined by 80 percent. This efficiency is unprecedented, but the methods used to achieve it have left animals exceedingly vulnerable to bacterial infection and disease.

The industrial operations that dominate modern food animal production confine hundreds and often thousands of animals in overcrowded and unsanitary facilities. In a single poultry house, tens of thousands of chickens or turkeys may be packed beak-to-beak. The enormous quantity of waste these animals generate is not removed until the birds reach market weight and a new flock arrives (about once every 45 days). Left for weeks, feces pile up in poultry bedding, constantly exposing chickens and turkeys to pathogens and harmful chemicals.

Raised indoors, poultry and swine cannot access the traditional forage for which their digestive systems have evolved. The animals instead receive artificial feeds based on corn and soybeans. The stress of overcrowding, poor nutrition, and the denial of normal animal behaviors weaken the immune systems of the animals, leaving them more susceptible to infection by the pathogens in their waste and on the animals with which they are cloistered.

The economic success of a production system so detrimental to its product is counterintuitive. The secret to its success has been, in no small part, the continuous feeding of small doses of antibiotics to food animals throughout their lives. These drugs help animals grow faster, and they also stave off infections linked to the squalid conditions in which food animals are raised. The misuse of antibiotics by the food animal industry is not just a means to make a quick buck; misusing these drugs is the lynchpin of the industrial model.

Missing the Point

If antibiotics could no longer be used for disease prevention, the food animal production industry would be forced to reform its production practices to raise healthy animals in other ways. The preventive use of antibiotics would no longer be "necessary." By eliding this fact in its guidance documents, the FDA has built public health policy around the needs of the industry rather than require the industry to reform itself to assure both human and animal health.

The guidance document defines disease prevention as follows: "the administration of antimicrobial drugs to animals, none of which are [sic] exhibiting clinical signs of disease, in a situation where disease is likely to occur if the drug is not administered" (emphasis added). The question of someone concerned about animal health should be, Why is disease likely to occur in the absence of an antibiotic? Asked the same question in the context of human health, an epidemiologist might consider such factors as sanitation, housing, and nutrition--three aspects of industrial food animal production that are sadly lacking.

The agency gives a revealing example of disease prevention: "if a veterinarian determines, based on a client's production practices and herd health history, that cattle being transported or otherwise stressed are more likely to develop a certain bacterial infection" (emphasis added), preventive use of an antibiotic may be recommended.

This example dances around important questions too. How might "production practices" contribute to the risk of developing bacterial infections? How might animals be "otherwise stressed" in ways that increase their susceptibility to infection and disease? These questions suggest a third: why should the food animal industry be allowed to use antibiotics to compensate for poor production practices and the stresses animals incur as a result?

In an earlier draft of the guidance document, the FDA described how a veterinarian should determine the appropriateness of using antibiotics for disease prevention. An important criterion was the availability of "evidence that no reasonable alternatives for intervention exist." The implication is clear. If there is evidence that improving the living conditions and nutrition of food animals could reduce the occurrence of bacterial infections, it would be better to do so than to use antibiotics in ways that endanger the public health.

Denmark provides clear evidence of alternatives. In 2000, the country banned the misuse of antibiotics over the strenuous objections of the Danish swine industry. There was an initial uptick in animal morbidity and mortality until the industry gave the animals more space, delayed weaning, fed them more nutritious diets, and made other improvements. Denmark remains the top exporter of pork products in the world today. FDA never seriously considered such alternatives, however. The agency tellingly removed the criterion from the final version of the guidance document.

The use of antibiotics to make food animals grow faster appears to be on its last legs, although much will depend on how quickly drug companies comply with the guidance documents and whether the food animal industry complies at all. For public health advocates, the fight now moves to the use of these drugs for disease prevention. This is a much steeper hill to climb: their misuse lies at the heart of industrial food animal production, and the FDA has abdicated its responsibility to stop it. The agency would like to declare victory and move on. It is clear that the agency, and we, have work to do.

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