Ban versus beast
CAFO supporters acknowledge that farm strains of drug-resistant bacteria could theoretically spread to people. But “I don't see this equating to human health risk”, says Scott Hurd, a veterinarian and epidemiologist at Iowa State University who has conducted multiple studies to assess the risk of drug-resistant bacteria spreading through meat production. He says that the average person has a greater chance of dying from a bee sting than of contracting MRSA from pork. Hurd argues that limiting the use of antibiotics on farms could be harmful to human health. Even Smith's grocery-store study found that meat sold as 'antibiotic free' had the highest levels of garden-variety S. aureus, suggesting that untreated animals harbour more pathogens. “Animals really do need to be treated,” Hurd says.
Nevertheless, regulatory authorities have clamped down on antibiotic use on farms. The European Union began phasing out antibiotics for growth promotion in the late 1990s. Denmark led the charge with a full ban in 2000. (China, however, which claims half the world's pig population, has yet to rein in antibiotic use.)
The bans' effects on drug resistance and human and animal health have been murky. Levy and other supporters of the bans say that the result in Denmark has been positive, pointing to data showing a drop in the use of antibiotics on farms and an increase in meat production. But opponents, including the Animal Health Institute, point out that the use of antibiotics to treat acute illness in Denmark has increased, as have animal deaths.
Last year, amid mounting pressure from several groups, including the National Resources Defense Council, based in New York, the FDA released new guidance calling for the “judicious use” of antibiotics on farms. The agency discouraged the use of antibiotics for growth promotion and urged label changes to the drugs and more veterinary oversight for their application. Not all the guidelines are yet approved, and compliance is voluntary. Nevertheless, the agency has suggested that it will enforce tougher rules if farmers and drug-makers do not adopt the guidelines within about three years. Few are satisfied with the FDA's policy. Pig farmers and meat-industry representatives consider the move a blow to farmers and animal welfare, and supporters of antibiotic restriction say that the voluntary guidelines do not go far enough. Scientists, meanwhile, have pressed the FDA to reveal more data on how farmers are using antibiotics, so far without success.
Smith, who is concerned that farmers are still overusing antibiotics, hopes that the results of her current research will sway their opinions. Antibiotics on farms can trigger the emergence of resistant strains, she says, and those strains turn up on meat, in grocery stores and in homes, and they can infect people. “For me, that's enough,” she says.
At the same time, Smith says that she sympathizes with CAFO operators who are trying to produce meat as safely and efficiently as possible. And although human health should take priority over farm animals, she says, farmers will be reluctant to change until researchers can come up with safe and cost-effective practices to replace the use of antibiotics. For now, Smith says, “we're kind of stumped”.