[In vitro comparative activity of five macrolides against 190 Branhamella catarrhalis strains]

We compared the in vitro activity of 5 macrolides against 190 strains of Branhamella catarrhalis; 48 strains were isolated at Centre Hospitalier, Aix-en-Provence, the 142 others were isolated during 1987, in 15 different Centres-Hospitaliers-Généraux in France. 153 strains were betalactamase producing strains; no difference in susceptibility to erythromycin was observed on betalactamase producing and non producing strains. Three active macrolides against 100% of strains were: erythromycin (MIC 50 = 0.25 mg/l - MIC 90 = 0.50 mg/l), roxithromycin (MIC 50 = 0.50 mg/l - MIC 90 = 0.50 mg/l) and josamycin (MIC 50 = 0.50 mg/l - MIC 90 = 1 mg/l); A lower activity was noted on midecamycin (mic 50 = 2 mg/l - MIC 90 = 2 mg/l) and spiramycin (MIC 50 = 4 mg/l - MIC 90 = 8 mg/l).