Bacteremic infections due to clindamycin-resistant streptococci

We have recently observed four patients with bacteremic infections due to group A streptococci that were highly resistant to clindamycin and only moderately susceptible to erythromycin. Two of the infections developed while the patients were receiving clindamycin. The organisms were not beta-hemolytic under standard conditions nor were they M or T typable. We urge that all streptococci isolated from patients with serious infections be grouped serologically and be tested for antibiotic susceptibilities, especially if therapy with antibiotics other than penicillin is to be considered.