Doctors: Strep bacteria suddenly resisting common antibiotic

Wednesday, April 17th 2002, 12:00 am
By: News On 6

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.

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

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 for many other antibiotics.

The jump in resistance began early last year at a Pittsburgh 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 M. Martin of the hospital's Division of Allergy, Immunology and Infectious Disease. ``Where it started, I don't know.''

The study was reported in Thursday'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.

``In may be occurring in other places across the country,'' she added.

Dr. Lincoln P. Miller, head of the Newark infectious disease outpatient clinic at University of Medicine and Dentistry of New Jersey, said the findings show doctors should limit use of all macrolide drugs.

``This is an important article because it indicates the impact of our antibiotic use on the bacteria around us,'' Miller said. ``I would hazard a guess and say (this resistance is) fairly widespread.''

Doctors have long warned that overuse of antibiotics is making some germs immune. 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.

In 1998, Martin began tracking group A streptococcus at the private elementary school, taking thousands of twice-a-month throat cultures from children. In January 2001, the doctors began seeing many samples of the same group A strain resistant to erythromycin _ in all, 48 percent over that winter. Forty-six of the students had the antibiotic-resistant form of strep throat.

In addition, a random check of samples from children treated for throat infections at Children's Hospital found 38 percent had the identical resistant strain.

In an editorial, Dr. Pentti Huovinen of Finland's National Public Health Institute wrote that prevalence of group A streptococcus that cannot be treated by macrolide drugs began increasing in 1990. When regulations limited their use, the resistance problem dropped sharply.