Strep bacteria in Pennsylvania outbreak proved difficult to kill

Associated Press

For the first time, doctors have documented a large-scale U.S. outbreak of antibiotic-resistant strep throat — an episode involving at least 46 Pittsburgh schoolchildren.

The jump in resistance was detected early last year at a private school, where roughly half the strep throat cases were found to be untreatable with erythromycin. All the children were successfully treated with other drugs.

"It definitely went from one kid to another in the school and it also spilled over into the community," said lead researcher Dr. Judith Martin of Children’s Hospital of Pittsburgh’s Division of Allergy, Immunology and Infectious Disease. "Where it started, I don’t know."

Until now, antibiotics have easily killed group A streptococcus, the bacteria that cause strep throat and life-threatening septic infections, so doctors at the hospital were startled by its sudden, widespread resistance to widely used erythromycin. The drug is commonly given to people allergic to penicillin.

Doctors suspect the strep bacteria also are becoming resistant to other popular drugs in the same antibiotic family, the macrolides. Their use is growing because they require only one dose a day, compared with three a day for many other antibiotics.

The study was reported in today’s New England Journal of Medicine.

Dr. Chris Van Beneden, an epidemiologist at the Centers for Disease Control and Prevention, said the CDC will investigate.

"It may be occurring in other places across the country," she said.

Doctors have long warned that overuse of antibiotics is making some germs immune to them. Antibiotic resistance has been growing in another type of streptococcus that causes pneumonia, but a recent survey of half the states found that less than 3 percent of group A streptococcus samples were resistant to erythromycin and closely related azithromycin.