American farmers would be forced to get prescriptions for livestock antibiotics, under a plan developed in Denmark and promoted by infectious disease doctors as a way to stem a rising tide of drug-resistant infections.Healthy livestock are routinely given antibiotics in the U.S. to promote growth and prevent illness. The practice, though, allows germs to mutate within their bodies, spreading into meat and swapping DNA with flora in the human gut. That’s a recipe for transferring resistance, said James Johnson, a University of Minnesota researcher at a medical meeting yesterday.Resistant infections cost the U.S. more than $20 billion annually, according to a 2009 study in the journal Clinical Infectious Diseases. By following a method used in Denmark that tracks data on livestock antibiotics, the U.S. may thwart resistance, said Lindsay Grayson, chief of the Interscience Conference on Antimicrobial Agents and Chemotherapy.“My main advice for the U.S. is that all antibiotics used on animals should be given only with a prescription,” said Henrik Caspar Wegener, the director of the National Food Institute in Denmark. “That’s not the case at the moment. Antibiotics are medicines. They should be prescribed by someone educated to make that decision.”Wegener spoke yesterday during a panel session at the conference in Chicago.By requiring prescriptions for all antibiotics, the U.S. Food and Drug Administration can make more-informed decisions about how the drugs are used and lead them to see where their use can be eliminated, he said. Additionally, more data may help officials persuade the U.S. meat-producing industry, which had 2009 sales of $154.8 billion, to change over, Wegener said.While Liz Wagstrom, chief veterinarian at the National Pork Producers Council, echoed the call for more surveillance, she said requiring prescriptions would be more difficult here than in Denmark, a country that’s smaller than the state of Iowa. The U.S.’s larger size and less homogenous population make tracking efforts more complex, she said.“Really, until we have data about uses and trends in resistance, we’re talking in generalities,” Wagstrom said in a telephone interview. For smaller producers and those in remote geographic areas, having a veterinarian prescribe every use could be difficult, she said.Sharon Curtis Granskog, a spokeswoman for the American Veterinary Medical Association, wouldn’t immediately comment, and Janet M. Riley, a spokeswoman for the American Meat Institute, referred comment to Wagstrom. Neither Gary Mickelson, a spokesman for Tyson Food Inc., the largest U.S. meat producer, nor Mike Martin, a spokesman for Cargill Inc., immediately returned calls or e-mails.Food infections sickened 48 million Americans last year, leading to 128,000 hospitalizations and 3,000 deaths, according to the Centers for Disease Control and Prevention.The Denmark program, dubbed DENMAP, would only be a first step, Denmark’s Wegener said. The European Union barred any non- therapeutic antibiotic use in livestock in 2006.A study two years later in the American Journal of Veterinary Research found that mortality rates among the animals didn’t change despite the EU ban on non-therapeutic use, which slashed use of the drugs by half. In 2010, the European Food Safety Authority reported that the prevalence of food-borne illness in Europe dropped in the four years after the ban.“For us, it is quite clear,” said Awa Aidara-Kane, the leader of the World Health Organization’s antimicrobial resistance group, in an interview. “Special attention should be paid to antimicrobial agents that are critically important for human infection.”Movement in U.S.There has been some movement toward more monitoring in the U.S. A Sept. 7 report from the U.S. Government Accounting Office gave the issue new prominence, recommending the U.S. Food and Drug Administration work with drug companies on a voluntary basis to increase veterinary supervision of antibiotics.Data collected by the U.S. Departments of Health and Human Services and Agriculture “lack crucial details necessary to examine trends and understand the relationship between use and resistance,” the report said.The GAO said the data collected by agencies don’t show what type of animals are getting antibiotics or for what purpose. The agency also said the data, are collected in a haphazard manner, “are not representative of food animals and retail meat across the nation and, in some cases, because of a change in sampling method, have become less representative” since a previous report by the GAO completed in 2004.The GAO investigators visited Wegener in Denmark, and met with farmers and veterinarians as well, he said.“We had a lengthy discussion about the situation in Demark,” Wegener said. “I just wonder if there is the political will to change anything about antibiotic use in the U.S.”The GAO endorsed an idea proposed last year by the FDA to work with drugmakers to limit access to antibiotics for animals and increase veterinary supervision. “Except for one $70,400 USDA project,” all other federal programs to educate producers and veterinarians use of antibiotics and alternatives have ended, the report said.