Activities of Telithromycin (HMR 3647, RU 66647) Compared to Those of Erythromycin, Azithromycin, Clarithromycin, Roxithromycin, and Other Antimicrobial Agents against Unusual Anaerobes

The comparative activity of telithromycin (HMR 3647) against 419 human anaerobic isolates was determined by the agar dilution method. At concentrations of ≤0.5 μg/ml, telithromycin was active against Actinomyces israelii, Actinomyces odontolyticus, Bacteroides tectum, Bacteroides ureolyticus, Bacteroides gracilis (now Campylobacter gracilis), Porphyromonas spp. (including Porphyromonas gingivalis and Porphyromonas macacae), Prevotella intermedia, Prevotella heparinolytica, and almost all Peptostreptococcus species. Clostridia showed species and strain variability, often with a biphasic pattern. Fusobacterium species, except Fusobacterium russii, were relatively resistant.