The rates at which oral antibiotics were prescribed to children under age 5 years were directly related to the rates of resistant Streptococcus pneumoniae cultured from acute otitis media cases in a study reviewing more than 200,000 prescriptions.
In two distinct populations in southern Israel that were followed for 5 successive years, a “remarkable” seasonal reduction in antibiotic prescriptions during the warm months was significantly associated with a marked reduction in antibiotic resistance rates in pneumococcal isolates, said Dr. Ron Dagan of Soroka University Medical Center, Beer-Sheva, Israel, and his associates (J. Infect. Dis. 2008;197:1094-102).
“In Jewish children, each monthly increase in 10 prescriptions per 1,000 children was associated with a 1.05-fold increase in the odds of penicillin resistance during that month. The corresponding odds ratio for erythromycin resistance was 1.04, and for multidrug resistance it was 1.04,” they wrote.
In an accompanying editorial, Dr. Cindy R. Friedman and Dr. Cynthia G. Whitney of the Centers for Disease Control and Prevention, Atlanta, wrote that these findings provide solid evidence that reducing antibiotic use can lead to a decrease in resistant pneumococcal infections. “The challenge now is for clinicians to reduce unnecessary use” of antibiotics, they wrote (J. Infect. Dis. 2008;197:1082-3).
The researchers reviewed all 236,466 prescriptions for oral antibiotics written during 1999-2003 for children aged younger than 5 years in seven large pediatric primary care clinics. Five of these were in urban Jewish centers and two in Bedouin townships. There was a 24% drop in the prescription rate during the warm months, compared with the cold months. The mean monthly antibiotic prescription rate was 291 per 1,000 children in the winter and 222 per 1,000 in the summer. Rates of antibiotic resistance showed a corresponding seasonal variation.
Although this pattern was seen in both populations, the urban Jewish population showed a much more pronounced—and statistically significant—seasonal variation in both prescribing rates and resistance rates than did the rural Bedouin population.
In the Jewish population, the rate of penicillin resistance was 43% in the cold months, compared with 29% in the warm months. The rate of erythromycin resistance was 29% in the cold months, compared with 20% in the warm months. And the rate of multidrug resistance was 25% in the cold months, compared with 15%. The differences were smaller and not statistically significant in Bedouin children.
These findings suggest that interventions to reduce antibiotic overuse “may reduce resistance in the community faster than previously thought,” they added.