Such use is especially important in huge, factory-type hog and poultry operations, which increasingly dominate U.S. meat production. Instead of being integrated into broader farming operations, animals by the thousands are raised in confinement and treated with antibiotics to stop the spread of diseases and promote growth. Moreover, organisms that are resistant to one drug are likely to become resistant to another, and organisms can pass on the resistance to other organisms. The New England Journal study reports widespread emergence in the U.S. of a strain of salmonella that is resistant to five major antibiotics. If the bacteria become resistant to all antibiotics, patients would be at the mercy of the disease.
Critics say such concerns are farfetched.
Dr. Lyle Vogel, of the American Veterinary Medical Association, is more cautious. To my knowledge there is no documented case of resistance developed in animals that has caused treatment failure in humans. But the potential does exist, and we are concerned about it. Both the veterinarians and the producers argue that antibiotics are important for guaranteeing a safe, abundant food supply. CDC's Angulo agrees that the dangers are still more potential than real.