Antimicrobial resistance in Streptococcus pyogenes isolates in Berlin.

A total of 212 clinical Streptococcus pyogenes isolates were tested for susceptibility to various antibiotics by agar dilution. The overall frequency of erythromycin resistance was 12.7%, being higher in isolates from children (18.9%) than in those from adult patients (10.7%). Similar results were found for clarithromycin, while 2.8% of the isolates were resistant to ciprofloxacin. All strains were susceptible to penicillin and cefotaxime. Of the erythromycin-resistant isolates subjected to the double-disc diffusion test for erythromycin and clindamycin, 35% expressed constitutive and 55% inducible resistance to clindamycin. Ten per cent were susceptible to clindamycin (M-phenotype). Thus, a high rate of macrolide resistance in S. pyogenes has emerged in Berlin.