High rate of erythromycin and clarithromycin resistance among Streptococcus pneumoniae isolates from blood cultures from Providence, R.I.

Four (5%) of 81 recent isolates of Streptococcus pneumoniae from the blood of adult patients but no isolates from pediatric patients (n = 51) were resistant (MIC, > or = 1 microgram/ml) to erythromycin. The MICs of clarithromycin were slightly lower than those of erythromycin, but there was complete cross-resistance. Routine testing and surveillance are needed to determine whether erythromycin resistance among S. pneumoniae isolates is increasing throughout the United States.