Comparative antianaerobic activities of the ketolides HMR 3647 (RU 66647) and HMR 3004 (RU 64004)

Abstract

HMR 3647 (RU 66647) and HMR 3004 (RU 64004), two ketolides, had MICa at which 50% of the strains are inhibited (MIC50s) of 0.06 to 0.125 μg/ml and MIC90s of 16.0 μg/ml against 352 anaerobes. MIC50s and MIC90s of erythromycin, azithromycin, clarithromycin, and roxithromycin were 0.5 to 2.0 μg/ml and 32.0 to >64.0 μg/ml, respectively. HMR 3647 and HMR 3004 were more active against non-Bacteroides fragilis-group anaerobes (other than Fusobacterium mortiferum, Fusobacterium varium, and Clostridium difficile.