F.D.A. Restricts Use of Antibiotics in Livestock

By GARDINER HARRIS
Published: January 4, 2012

WASHINGTON — Federal drug regulators announced Wednesday that farmers and ranchers must restrict their use of a critical class of antibiotics in cattle, pigs, chickens and turkeys because such practices may have contributed to the growing threat of bacterial infections in people that are resistant to treatment.

The medicines belong to a class of antibiotics known as cephalosporins and include such brands as Cefzil and Keflex. They are among the most common antibiotics prescribed to treat strep throat, bronchitis, skin infections and urinary tract infections. Surgeons also often use them before surgery to prevent bacterial infections.

The drugs’ use in agriculture has, according to many microbiologists, led to the development of bacteria that are resistant to the drugs’ effects, a development that many doctors say has endangered the lives of patients.

Antibiotics are often added to animal feed and are used routinely to encourage rapid growth of livestock, but officials at the Food and Drug Administration have been increasingly vocal in their concerns that overuse of antibiotics in agriculture is endangering human health. The agency proposed rules in 2010 to slow the use of penicillin, tetracycline and other antibiotics simply to promote growth or prevent disease in feed animals, but those rules have yet to be made final.

Cephalosporins are not used as widely among livestock as penicillin, since they still require a prescription from veterinarians. But the drugs are routinely injected into fertilized eggs and are also used in large doses to treat various infections in cattle.

The F.D.A. announcement on Wednesday has the effect of restricting some but not all uses of cephalosporins in agriculture and is therefore a modest step that is likely to please some consumer advocates but lead others to grumble that the agency needs to do much more.

"We believe this is an imperative step in preserving the effectiveness of this class of important antimicrobials that takes into account the need to protect the health of both humans and animals," said Michael R. Taylor, deputy commissioner for foods at the agency.

The F.D.A. initially proposed its cephalosporin restrictions in 2008 but withdrew the rule before it became effective because of opposition from farmers and ranchers. The rule announced Wednesday is less strict than the one proposed in 2008; it allows for unrestricted use of cephapirin, an older member of the class of cephalosporins that is not thought to contribute significantly to antimicrobial resistance. And the new rule allows veterinarians to continue to use the drugs to treat many illnesses in feed animals as long as they follow guidelines about dosing and duration of use. The new rule also allows for use of the drugs in ducks and rabbits.

Agricultural organizations have disputed claims that antibiotics are overused in animals and that those uses have contributed to antimicrobial resistance, saying that farmers and ranchers use the medicines judiciously. While legislation has been proposed in Congress to restrict the use of antibiotics in agriculture, powerful agricultural interests have blocked these bills and consecutive administrations have been unwilling to challenge these interests by using F.D.A. rules to crack down on antibiotic use in feed animals.

http://www.nytimes.com/2012/01/05/he....html?_r=1&hpw