Doctors weigh in against antibiotics in animal feed

Bacon for breakfast? Chances are, it came from a hog on drugs. Planning chicken or steak for dinner? It could well come from an animal repeatedly fed antibiotics.

For decades, ranchers and farmers have used medicines to speed up the growth of their animals. Now, pressure is building to stop the practice. It's part of a much larger challenge for the medical world: The more often doctors prescribe antibiotics, the more likely it is, scientists say, that bacteria will develop resistance to them, and they will lose their effectiveness for humans.

"The whole medical profession is depending on prescribing antibiotics, and that's dangerous," says Roderick Mackie, professor of microbiology at the University of Illinois at Champaign-Urbana.

This week, the American Medical Association called for a partial ban on feeding antibiotics to animals. The group joins a long list of organizations that have called for such a ban during the past 20 years. The European Union prohibits the practice.

"We just have a huge amount of antibiotics being used, and they're being used in such a way that they're finding their way all over the farm," says David Wallinga, senior scientist at the Institute for Agriculture and Trade Policy, a nonprofit group based in Minneapolis.

Agriculture represents a tempting first target in the battle to reduce reliance on antibiotics. Currently, farmers often feed them to their cattle, hogs, and chickens - often to spur growth, as well as for health reasons.

A recent US Agriculture Department survey of research found that hogs receiving the medicines grow 10 percent faster than non-dosed hogs - a boon to farm profits. By one estimate, 7 in 10 large hog farms use the drugs in the first phase of growth, and slightly more than half use them at a later stage.

But with hogs in particular, the antibiotics used are very similar to the ones used for medical treatment of people.

So far, no one has proved that such feeding boosts resistance to bacteria harmful to humans. No one even knows how much antibiotics humans or animals consume. The industry and the US Centers for Disease Control estimate that animals consume one pound of antibiotics for every two pounds humans do. In February, the Union of Concerned Scientists released a study suggesting that farm animals may consume up to eight times the antibiotics humans do.

The dilemma for policymakers is whether to wait for scientists to prove a link, or assume the worst and take immediate action. "We ought to make policy changes based on facts and sound science," argues Ron Phillips, spokesman for Animal Health Institute, a trade group representing the makers of animal-health medicines and vaccines.

But Dr. Mackie of the University of Illinois wants more-immediate action. "Feeding sub-therapeutic levels [to animals] is not prudent and it's not good policy."

Earlier this year, he published papers showing a link between hog manure on an Illinois farm and bacteria carrying a gene resistant to a class of antibiotics used for humans. The bacteria were found in groundwater, meaning they could easily spread, although scientists must find several more links before they can prove agricultural feeding threatens human medical treatment.

Meanwhile, the livestock industry is bracing for more pressure to ban the practice. "I think the usage of antibiotics in livestock feeding is going to be scrutinized very closely," says Gilbert Hollis, professor of swine nutrition at the University of Illinois.

(c) Copyright 2001. The Christian Science Monitor