Will Healthier Birds Mean Sicker People?Lars Hansen
With drug-resistant strains of bacteria proliferating wildly, doctors treasure the few antibiotics still capable of knocking out dangerous diseases. They try to use them sparingly to reduce the chances that bacteria will develop resistance. Doctors are especially protective of new synthetic antibiotics called fluoroquinolones--the only drugs left that can conquer certain virulent strains of dysentery and typhoid fever. One type is being deployed against an epidemic of dysentery in Zaire, Burundi, and Rwanda that's killing 15% of its victims.
That's why some public-health officials were alarmed on Aug. 18 when the Food & Drug Administration approved the use of a type of fluoroquinolone--sarafloxacin--against bacterial infections in poultry. They worry that the move will make sarafloxacin ineffective against human disease: Bacteria in poultry will become resistant to the antibiotic, and then could pass on the trait to other bacteria that cause diseases such as dysentery. "We're very concerned," says Mitchell L. Cohen, director of bacterial and mycotic diseases at the Centers for Disease Control (CDC) in Atlanta.
Skeptics also question whether the benefits of the FDA move warrant the risk. Feeding chickens and turkeys sarafloxacin, which is sold by Abbott Laboratories under the brand name SaraFlox, isn't intended to make poultry safer to eat: the strain of E. coli bacteria it controls doesn't harm people anyway. Rather, by saving infected flocks, it may slightly reduce the supermarket price of chicken--and, not incidentally, help the profitability of poultry producers. "The industry is very pleased," says Steve Pretanik, director of science and technology for the National Broiler Council, trade group for the $15 billion chicken production and processing industry. Abbott Labs declined comment.
The FDA says it's aware of the threat from drug-resistant bacteria. In a first, the agency will monitor use of the antibiotic with the CDC and the Agriculture Dept., and may halt its use if resistance develops. Use of the antibiotic also will be limited: It can only be used to treat outbreaks of disease in poultry, not as a preventative. And just 38 veterinarians will be allowed to prescribe the antibiotic--for an estimated 2% of the 7.5 billion chickens and turkeys produced annually in the U.S. "We intend to regulate this very strictly," said Stephen F. Sundluf, director of the FDA's Center for Veterinary Medicine.
Poultry producers, plus a good number of academics, say the emergence of drug-resistant bacteria that harm people is solely due to overuse of antibiotics in treating human infections. "The use in animals has very little if any impact on health in man," says Virgil W. Hays, a retired professor from the University of Kentucky's animal science department. As evidence, he says that farmers who spend time near animals don't seem to have a higher occurrence of antibiotic-resistant infections.
But many doctors argue that the lack of proof of a linkage is the result of inadequate research. They say a bacterial strain that withstands sarafloxacin is likely to develop resistance to the whole class of fluoroquinolones. Says Dr. Stuart B. Levy, a professor of medicine and of molecular biology and microbiology at Tufts University School of Medicine: "Just keep using the antibiotic, and the resistance will come."
WEIGHING RISKS. Levy worries that once farmers begin to see how effective SaraFlox is, they won't want to limit their use of it. Agricultural sales of antibiotics already total some $500 million a year (chart), and, in volume, roughly equal the amount used by humans. If antibiotics weren't used for growth promotion in animals, retail prices for chicken and pork might be 1% to 2% higher, economists say.
But some scientists, including Gail H. Cassell, a University of Alabama microbiologist who studied the topic for the congressional Office of Technology Assessment, question whether such benefits outweigh the risks to human health. Given the potential perils, such skeptics wonder, is it really so important to save 2 cents on a pound of chicken wings?