Antibiotics in Food Animals: FAQ

Antibiotics in Food Animals: FAQ

By Daniel J. DeNoon
WebMD Health News

Reviewed by Laura J. Martin, MD

Jan. 6, 2012 -- Food animals get 80% of the antibiotics used in the U.S. -- mostly in ways that can lead to the growth of drug-resistant superbugs.

Emerging drug resistance in bacteria is one of the world's greatest health threats, according to the CDC, the FDA, the World Health Organization, and a wide range of medical professional societies.

These groups cite "strong evidence" that many of these hard-to-treat germs arise in food animals and spread to humans. For this reason, the FDA argues strongly against unwise -- "injudicious" -- use of antibiotics in livestock. Yet over 80% of animal antibiotics are used in these ways.

In January 2012, the FDA prohibited some uses of the cephalosporin class of antibiotics in food animals. But these antibiotics make up less than a fraction of 1% of the 15,000 tons of antibiotics used in U.S. food animals each year.

This raises important questions. Here are WebMD's answers.

Why are antibiotics used in food animals?

There are two main reasons: To promote animal health, and to make animals grow faster.

The FDA has no problem with the antibiotics used to treat disease in animals. And it has no problem with antibiotics used under the direct supervision of a veterinarian who is treating specific animals.

But over 80% of antibiotics used in food animals is put into their feed or water by livestock producers, almost always on a herd-wide basis. This makes animals put on weight faster even if they don't eat more food.

Such "production use" of antibiotics is what the FDA, in its June 2010 guidance to the industry, deemed unwise or "injudicious."

How can antibiotics given to animals create drug-resistant germs?

If you get an antibiotic prescription from your doctor, you'll be warned to take every single one of the pills exactly as prescribed. That's because the last few pills mop up the most drug-resistant germs. If you take too low a dose, the most resistant germs remain.

The same thing happens in animals. Veterinarians treat sick animals with appropriate doses of antibiotics.

But when antibiotics are used to make animals grow faster, they are given at low doses over long periods of time. That's a recipe for growing drug resistant bacteria in food animals.

Can drug-resistant bacteria in food animals find their way to humans?

There are some researchers, such as an expert panel of the Institute of Food Technologists, who say the odds are low that any of these bugs will find their way into humans. But in testimony before Congress, the USDA, the FDA, and the CDC all said that the use of antibiotics in food animals leads to infections with drug resistant bacteria to humans.

And in a letter to Congress, 14 health groups -- including the American Medical Association and the American Academy of Pediatrics -- said "overuse and misuse of important antibiotics in food animals must end, in order to protect human health."

The World Health Organization has also warned that overuse of antibiotics in food animals can lead to drug-resistant infections in people.

Didn't the FDA ban use of one antibiotic in food animals?

In January 2012, the FDA banned certain uses of cephalosporin antibiotics in food animals effective April 5, 2012.

The ruling prohibits giving food animals the kinds of cephalosporins used to treat disease in humans or in pets. Exceptions allow off-label use by veterinarians to treat specific diseases, and allow the use of an older cephalosporin called cephapirin, which is not used in humans.

Cephalosporins are not one of the antibiotics used to increase animal growth.

Cephalosporins are important human drugs introduced in 1964. They are often used to treat pneumonia. Cephalosporins are also used to treat ear, skin, urinary tract, and other infections.

In 2010, U.S. meat and poultry producers used 27 tons of cephalosporins. That sounds like a lot. But it's only a fraction of the 14,600 tons of antibiotics used in food animals that year.

One consumer group called the FDA action a step forward -- but only a baby step.

Will the FDA ban use of other antibiotics in food animals?

There is no indication that the FDA plans to ban food-animal use of other antibiotics already approved for such uses.

Antibiotics have been used for what the FDA now calls "injudicious uses" since the 1950s. In the now famous "Swann Report," U.K. researchers in 1969 concluded that feeding low-dose antibiotics to animals posed a health risk to humans.

The U.S. government in 1970 formed its own task force to look at the issue. Eventually -- in 1977 -- the FDA issued a formal finding that all animal use of penicillins and low-dose animal use of tetracyclines should be banned.


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