Antibiotic Resistance
Seen As Risk In
Food Supply
SAN FRANCISCO (Reuters) - The increased use of antibiotics in food animals is boosting the risk that dangerous "superbugs" resistant to drug treatment could be passed along to humans, scientists said on Monday. "It's not just a single pig or a single cow. It's a whole food commodity issue," Michael Osterholm, CEO of the Infection Control Advisory Network, told a news conference at a scientific meeting here. "Red meat, white meat, produce -- any commodity stream can play a role."
Scientists both in Europe and the United States have raised questions over the treatment of food animals with antibiotics, which farmers use widely both to fight animal illness and as part of animal feed to promote growth.
The European Union banned four antibiotics used in animal feed last December, hitting multinational drug companies Rhone Poulec, Pfizer, Eli Lilly's Elanco Animal Health and Alpharma and potentially costing them hundreds of millions of dollars in lost sales.
In the United States, authorities have moved more slowly, with the Food and Drug Administration monitoring the veterinary use of antimicrobial drugs with an eye toward regulating those drugs seen most likely to create resistant bacteria which could lead to human illness.
Bacteria which shrugs off one of the most powerful known antibiotics -- vancomycin -- has been found in some U.S. chicken feed, and research on pigs, cows and chickens has revealed signs that drug-resistant strains of salmonella, campylobacter and other bacteria are also spreading through animal populations.
In a series of reports at the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) here, scientists presented new findings indicating that the problem is growing more complex as governments try to assess how much of a threat dinner may really pose to public health.
In a study at the University of Antwerp, researchers found that samples of chickens, pigs and turkeys turned up "alarmingly high" anti-microbial resistance rates among strains of campylobacter bacteria, which are a major cause of human gastroenteritis and diarrhoea.
"There is growing scientific evidence that the use of antibiotics in food animals leads to the development of resistant pathogenic bacteria that can reach humans through the food chain," the study's authors concluded.
Another study at the University de la Rioja in Spain found a relatively high rate of antibiotic resistance in E.coli bacteria strains obtained from broiler chickens compared with those found in humans or their pets -- a difference the researchers said could be associated with the more widespread use of antibiotics in farm chickens.
This year, U.S. researchers in Minnesota reported a rise in human gastrointestinal illness caused by antibiotic-resistant campylobacter bacteria which they tied directly to the increase in quinolone-type antibiotics given to chickens.
Stephen Sundlof, director of the FDA's Centre for Veterinary Medicine, said the agency is working with the Centres for Disease Control to determine the actual risks posed by antimicrobial use in farm animals and hoped to establish regulations aimed at limiting the use of drugs which might eventually lose effectiveness in treating human illness.
The go-slow approach has pleased the makers of animal drugs, who say there simply is not enough evidence to back the idea that farm animals could become a stealth health threat.
"We would not agree to outright bans on these products. We need more data," said Richard Carnevale, a spokesman for the Animal Health Institute, an industry group. "We support prudent use (of antibiotics). We don't want to see precipitous action against products that are needed for animal treatment."