WASHINGTON – US Sen. Dianne Feinstein introduced a bill that would stop the use of antibiotics in the feed and water of food animals that are not sick.

The Preventing Antibiotic Resistance Act of 2013 charges the Food and Drug Administration with enforcement, and requires drug companies and agriculture companies to demonstrate that antibiotics are being used to treat sick animals and not as a growth promotant.

“Antibiotics are the closest thing to a ‘silver bullet’ in human medicine given their ability to wipe out a wide variety of bacterial infections, but we are in danger of losing this weapon in the fight against infectious diseases,” Feinstein said in a statement on her web site. “When antibiotics are fed in low doses to animals, only the strongest, most resistant bacteria are left behind to reproduce. By the time these resistant pathogens make their way from the animals into our communities, the infections can be costly to treat or untreatable all together.”

The proposed legislation:

• Directs the Food and Drug Administration to prohibit the use of antibiotics in ways that accelerate antibiotic resistance;

• Requires drug companies and producers to demonstrate they are using antibiotics to treat clinically diagnosable diseases—not just to fatten their livestock;

• Applies restrictions to only the limited number of antibiotics that are critical to human health. Any drug not used in human medicine is left untouched by this legislation; and

• Preserves the ability of farmers to use all available antibiotics to treat sick animals. If a veterinarian identifies a sick animal, or a herd of animals that are likely to become sick, there are no restrictions on what drugs can be used.

Antibiotic resistance has been the subject of fierce debate. Consumer groups such as the Consumers Union, the policy and advocacy arm of Consumer Reports, has called for major reductions in the use of antibiotics in food animal production on concerns that the overuse of antibiotics promotes the spread of drug-resistant "super bugs". But advocates in the agriculture industry say the issue of antimicrobial resistance is complex, and there is no definitive link between antibiotic resistance and the use of antibiotics in animal agriculture. Industry has supported the judicious use of antibiotics.