When the federal Food and Drug Administration approved using a common antibiotic to treat sick chickens, critics warned that poultry farms might become the breeding grounds for a potent new strain of food-borne illnesses in people.
Five years later, the FDA has concluded the critics were right. It now wants to ban the drug.
But before the ban became final yesterday, pharmaceutical giant Bayer Corp., which makes the drug used to treat poultry and people, moved to block the agency.
By requesting a hearing on the FDA's decision to ban the antibiotic Baytril, the company kicked off a bureaucratic process that will last months or years. Before it's over, public health activists say, the spread of drug-resistant Campylobacter bacteria in the U.S. food supply may pose a serious threat to human health.
Bayer disagrees. "We think their facts are wrong," said Margo Barnes, a company senior vice president. Bayer's data show no link between the use of the drug in chickens and the rising failure rate of the drug in human illness, she said, and the company wants more time to review the FDA's evidence.
Delmarva Poultry Industry executives say Eastern Shore chicken farmers would be hurt by a ban because the Bayer antibiotic is the only drug available to treat potentially deadly respiratory infections.
"If this tool is taken out of the toolbox, we could have increased mortality and increased sickness in flocks," said Bill Satterfield, the association's executive director. "We think the FDA is kind of jumping the gun on this."
Campylobacter, one of the most common food-borne illness in the United States, strikes about 2 million people a year with gastrointestinal symptoms. The FDA reports that surveys in Maryland and two other states show between 40 percent and 80 percent of all supermarket chicken carry the bacteria, though it can be eliminated by careful washing and cooking.
In the elderly and people with weakened immune systems, Campylobacter can be fatal. Doctors say antibiotics closely related to Baytril, called fluoroquinalones, are the best treatment.
In 1990, about one in 100 cases of Campylobacter was resistant to the drugs. But after fluoroquinalones were approved for use in chickens in 1995, resistance shot up. By 1999, one in every six human cases of Campylobacter infection was resistant, the FDA found.
"The rapidity of this change is scary," said Dr. Glenn Morris, chairman of the epidemiology department at the University of Maryland School of Medicine.
Campylobacter doesn't bother chickens, poultry veterinarians say. But when some birds in a flock get unrelated respiratory infections, veterinarians often put Baytril in the whole flock's drinking water. As a side effect, organisms such as Campylobacter are killed.
"But all of the Campylobacter is not killed all of the time, and the more resistant strains survive ... and wait for us in the supermarket," said Dr. Richard Wood, a member of the FDA's veterinary advisory committee and a food safety activist.
The stronger strain of Campylobacter can spread to flocks that have never been treated with Baytril, the FDA says.
Dr. G. Donald Ritter, a veterinarian and chairman of the Delmarva Poultry Industry's poultry health committee, says a typical Eastern Shore company with 150 chicken houses might use Baytril on one flock per week. The treatment is expensive, so "it's our last bullet," he said. He said there's no proof that the drug's use in poultry has caused the rise in human resistance.
The American Medical Association has joined other public health organizations in endorsing the ban on Baytril to treat poultry. Some activists say the case is the clearest example so far of a rising problem: the spread of antibiotic-resistant diseases because of modern livestock-raising practices.
Cattle, pork and poultry producers routinely use antibiotics developed to treat human illnesses. Most common is low-level dosing with erythromycin, sulfa and other drugsto encourage weight gain.
Some experts say the drugs are now so widely dispersed in food and water that they're triggering the growth of "superbugs" - antibiotic-resistant human illnesses.
"It raises a horrifying vision ... in which there are organisms circulating in the human population for which there is no antibiotic treatment at all," said Richard Levinson, associate director of the American Public Health Association. He and other experts would like a ban on the low-level dosing of healthy animals as well.
But veterinarian Ritter said such a ban isn't backed by science and would hurt consumers by boosting meat and poultry prices.