Bugs Behaving Badly
Antibiotics are aging, and bacteria are learning to fight them off
Methicillin-resistant S. aureus is being transported into hospitals from outside, not just sent into communities from hospitals. A report to be published later this month in the Journal of Infectious Diseases states that as many as 90 million healthy people, or nearly one third of the U.S. population, carry S. aureus as a passenger in their noses. And in more than 2 million of them, the bug is the resistant strain. Based on cultures of nasal samples taken from some 9,600 individuals selected at random in 2001 and 2002 as part of an ongoing national health and nutrition survey, the study was the first to determine the precise extent to which the microbe has made itself at home throughout the population. The answer, clearly, is: very at home.
Overload. What has exacerbated matters is Americans' well-documented tendency to think they need an antibiotic for every cold or cough or child's sore throat or earache. And physicians tend to go along, arguing that they don't have time to educate patients on the folly of taking an antibiotic. The larger the quantity of antibiotics prescribed, the greater the opportunity for bacteria to form resistant mutations. Yet in an analysis in JAMA published in November, more than half of children who came to a doctor's office, a hospital outpatient department, or an emergency room between 1995 and 2003 because of a sore throat left with an antibiotic.
Such reflexive prescribing is unsound medicine. Most sore throats are caused by viruses, which don't respond to antibiotics, so the majority of the children wouldn't have been helped. And many of the kids who did take an antibiotic, the JAMA analysis found, were prescribed one that was not among those specifically recommended by physician groups and the CDC.
Surely a prescription is justified for an adult who's been coughing for more than a week, is running a fever, and--skip ahead to the next sentence if squeamish--is hacking up greenish phlegm. But no. The largest study to date of the merits of antibiotics for such patients, published in JAMA in June, found the cough didn't go away or the severity of the symptoms lessen any sooner in a group of patients on antibiotics than in another group that didn't get them. "Perhaps it is not a coincidence," suggested family physician Mark Ebell in an accompanying edi-torial, "that manufacturer-sponsored placebo-controlled trials of newer anti-biotics for acute bronchitis in healthy adults are absent from the literature."
Some researchers, among them Stuart Levy, a microbiologist at Tufts University School of Medicine and founder and president of the Alliance for the Prudent Use of Antibiotics, worry about another source of antibiotic resistance: antibacterial household products. Between 300 and 550 germ-fighting products, such as liquid soaps, laundry detergents, and even toothbrushes, have been introduced every year since 1999, according to Datamonitor, a Naples, N.Y., market research firm.
Levy cautions that trying to stamp out germs in healthy households could breed tougher bugs that might also resist anti-biotics. A study he coauthored, published in October in Emerging Infectious Diseases, found no such problem in 224 households after a year of use. But Levy argues: "That wasn't long enough. Vancomycin was used for years before resistance emerged." It's worth noting that the cleaners aren't anything special. The study found them no better at exorcising bacteria than plain soap.
advertisement
