A coalition of health, consumer, agricultural, environmental, humane and other advocacy groups is calling for the passage of a law banning the use of antibiotics in animal feeds to prevent the emergence of drug-resistant bacterial diseases.

The Chicago-based Keep Antibiotics Working (KAW) is backing the "Preservation of Antibiotics for Medical Treatment Act" (PAMTA) of Edward Kennedy, D-Mass, and Olympia Snow, R-Maine. The bill phases out in two years antibiotics for humans used to primarily promote the growth of pigs, sheep, chicken and cattle.

The PAMTA amends the Federal Food, Drug and Cosmetic Act to withdraw approvals for feed-additive use of penicillins, tetracyclines, macrolides, lincosamides, streptogramins, aminoglycosides, and sulfonamides.

KAW claimed that major antibiotic classes such as tetracyclines and the Cipro-like fluoroquinolones have already been rendered ineffective to humans.

Since 1963, British researchers linked the emergence of drug-resistant strains of salmonella in humans to erythromycin, penicillin and streptomycin fed to cattle. According to the San Francisco Chronicle, critics also warned that the use of antibiotics in feed at low dosages helps to breed resistant bacteria in the gut of farm animals - threatening the future of these drugs for use in animals or humans.

KAW is also backed by environmental groups and the American Medical Association.