Washington - Twenty-five pharmaceutical companies are voluntarily phasing out the use of antibiotics for growth promotion in animals processed for meat, the Food and Drug Administration said Wednesday.Citing a potential threat to public health, the agency in December asked 26 companies to voluntarily stop labelling drugs important for treating human infection as acceptable for animal growth promotion. The FDA did not name the one company that has not agreed to withdraw or revise its drugs.The companies will either withdraw the drugs from animal use completely or revise them so they would only be able to be used with a veterinarian's prescription.Many cattle, hog and poultry producers give their animals antibiotics regularly to make the animals grow faster and ensure that they are healthy.Withdrawing the animal drugs is designed to limit antibiotic-resistant diseases in humans as that resistance has become a growing public health problem. Repeated exposure to antibiotics can lead germs to become resistant to the drug so that it is no longer effective in treating a particular illness.In September, the Centres for Disease Control and Prevention released estimates that more than 23 000 people a year are dying from drug-resistant infections.The biggest risk is from germs spread in hospitals, and it's not clear how much of the problem is related to the use of drugs in animals that become meat. But the FDA has said this is one step toward addressing the problem.FDA said it was working with industry on the issue because it was an easier and faster route than the protracted regulatory process. Two of the leading manufacturers of animal antibiotics, Zoetis and Elanco, said they would comply.The FDA said the 25 companies represent 99.6% of the supply the agency is targeting.Consumers increasingly have clamoured for antibiotic-free meat. McDonald's, among other companies, has moved to limit the drugs in the animals that supply their meat, pushing many animal producers to go along.Some advocacy groups said the FDA needs to go even further to curb animal antibiotics, including limiting companies who use them for disease prevention when holding animals in crowded conditions. The current guidelines address antibiotic use for growth promotion.