Resistant Bugs

Sunday, March 11, 2007

EVER SINCE Ernst Chain and Howard Florey isolated penicillin in 1939, inaugurating the era of antibiotics, harmful microbes have steadily developed resistance to even the most robust bacteria killers. The more often a particular antibiotic is administered, the more likely that bacteria will adapt. So, along with the continual development of new antibiotics, the best way to preserve the efficacy of medications that treat dangerous infections is to use them as sparingly as possible. That's why your doctor might not prescribe a course of amoxycillin for your sniffles.

But The Post's Rick Weiss reported last week that the Food and Drug Administration might do the exact opposite. The FDA is considering approval of cefquinome, a powerful antibiotic, to treat a common bovine infection. Never mind that there are already 12 medications on the market to treat the illness, bovine respiratory disease, or that it would be more effective to simply house cows in more sanitary conditions. FDA officials are not supposed to discriminate against drugs because their purposes might overlap with others. Nor can they tell farmers how to raise their livestock.

What the FDA can do, however, is alter its self-imposed rules that prevent the agency from fully considering the public health risks of approving this antibiotic for use in animals. The FDA's current rules say that the agency can deny approval if giving the medication to livestock would threaten the efficacy of a major antibiotic in the treatment of food-borne illnesses in humans.

But overusing cefquinome might undermine a similar antibiotic for humans, cefepime, that is an essential medication for treating many infections that are not classified as food-borne but are nevertheless very dangerous. James E. Leggett Jr., an infectious-disease specialist whom the FDA brought in to advise on the cefquinome issue, points out that risk analyses compiled according to FDA guidelines do not consider whether giving cefquinome to cows would encourage resistance to it and other valuable antibiotics in some of the bacteria that live in -- and are excreted from -- the bovine gut, such as E. coli.

Instead of ignoring these risks, the FDA should adopt the more sensible standard that the World Health Organization recommends, which would allow the FDA to reject drugs that might undermine an antibiotic important in fighting "serious human disease," food-borne or not. With a fuller picture of how dangerous widespread use of cefquinome in cows might be, the FDA can make a better decision.

© 2007 The Washington Post Company