WHILE the U.S. Food and Drug Administration is recognizing the growing threat of antibiotic resistance, its new proposal to limit the use of antibiotics in animals raised for food could have a greater impact on the price of food than on public health.
The Centers for Disease Control and Prevention recently reported that in the U.S. there are approximately 2 million infections and 23,000 deaths annually that are attributable to antibiotic-resistant microbes.
Both human and veterinary medical practices contribute to this problem. But food animals are reliably linked to only three of 17 infectious agents identified by the CDC and to just 7.5 percent of total deaths. Clearly, antibiotic use in animals is only a piece of this story.
According to FDA figures from 2010 and 2011, roughly 13,500 tons of antibiotics were sold annually in the U.S. for use in animals, while 3,600 tons were sold for human use. Most of the veterinary antibiotics were probably used in food-animal production. Of this total, 28.8 percent were ionophores that confer absolutely no risk for resistance to medically important antibiotics, while 42 percent of sales were for tetracyclines. Many of these antibiotics were probably used to prevent disease while improving animal growth and the efficiency of feed conversion by as much as 10 percent.
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Concerned about antibiotic resistance, the FDA wants to stop the use of medically important antibiotics for reasons other than the treatment, control and prevention of specific diseases in food animals.
Implemented over three years, this policy would prohibit over-the-counter sales of all new in-feed and in-water products for food-animal production if they include medically important antibiotics. These products would instead be sold under a veterinary food directive or as prescription drugs — both of which require veterinary oversight.
While these proposed changes are potentially beneficial in the face of increasing antibiotic resistance, no one knows if they would result in any public health benefits.
It is, however, a potential game-changer for American food-animal producers. Because of increased veterinary costs and loss of production gains attributed to antibiotics, food prices would increase.
Rural producers with limited access to veterinarians would need assistance to cope, while small producers may be squeezed out of the market. If prices increase enough, consumers could favor cheaper imported foods for which we have limited regulatory oversight. This would also result in job losses for the U.S.
Some people have argued that, until now, allowing antibiotic use for growth and efficiency gains has enabled producers to limit the costs of disease and avoid investments in better husbandry and management practices. Some have suggested that food producers made production gains in part because antibiotics mitigate for unhealthy husbandry conditions.
The argument goes that when antibiotics can’t be used for growth promotion, then producers are forced to adopt better housing conditions and other strategies to make up for the loss of growth promoters.
It is also possible that growth promoters work largely because they do prevent disease. If so, then growth promotion could be redefined as disease prevention, which is a practice that is allowed under the proposed FDA policy.
In the final analysis, however, using antibiotics to promote growth is probably not a major threat to public health. Therapeutic use of antibiotics in both human and veterinary medicine is the biggest driver of medically important antibiotic resistance, as is the indiscriminate use of antibiotics in countries that lack any regulatory oversight.
We would be better served by expanding beyond the prudent-use mantra and dramatically increasing our research investment into alternative strategies, such as developing vaccines, probiotics and infection-control strategies that limit the need for antibiotics for both human and veterinary medicine.
Douglas Call, a professor of molecular epidemiology in the Paul G. Allen School for Global Animal Health at WSU, is researching antibiotic resistance in the U.S. and overseas.