IN-VITRO ACTIVITY OF DIRITHROMYCIN AGAINST CHLAMYDIA-PNEUMONIAE

The in-vitro susceptibilities of 12 strains of Chlamydia pneumoniae we re determined for dirithromycin, a new macrolide antibiotic, erythromy cyclamine, its active metabolite, and erythromycin. Both dirithromycin and erythromycyclamine had an MIC90 of 2 mg/L, as compared with 0.062 mg/L for erythromycin. The combination of dirithromycin and erythromy cyclamine appeared to be additive. Determination of the role of dirith romycin for the treatment of C. pneumoniae infection will depend on th e results of prospective, controlled studies utilizing culture.