[Isolated susceptibility of Streptococcus pyogenes to 3 macrolides]

Erythromycin is considered the drug of choice in the treatment of streptococcal pharyngitis in patients allergic to penicillin. However, in recent years several publications, especially in Finland and Italy, showed high resistance rates of S. pyogenes isolates to erythromycin and other new macrolides. To evaluate the situation in Israel, we checked the MIC of isolates from patients with tonsillitis during 1996. E-test results showed an MIC-50 of 0.23, 0.13 and 0.47 mcg/ml for erythromycin, clarithromycin and roxithromycin, respectively and a MIC-90 of 0.37, 0.23 and 0.78 mcg/ml. Only 2 isolates (2.1%) were partially or completely resistant to all 3 antibiotics. We conclude that empiric therapy with macrolides in Israel is still a viable option and can be recommended in S. pyogenes tonsillitis for patients allergic to penicillin.