In-vitro activity of azithromycin against Chlamydia trachomatis

We evaluated the efficacy of azithromycin, erythromycin and doxycycline in controlling in-vitro propagation of Chlamydia trachomatis in HeLa 229 cells. Eight recent clinical isolates of C. trachomatis and two fast-growing strains were tested with inocula of 10 super(3)-10 super(5) inclusion forming units per well of a 96-well microtitre plate. C. trachomatis) inclusions were detected by an immunoperoxidase-antiperoxidase procedure (PAP), including a genus-specific monoclonal antibody. MIC ranges were 0 multiplied by 064-0 multiplied by 25 mg/l azithromycin, 0 multiplied by 064-0 multiplied by 128 mg/l erythromycin and 0 multiplied by 016-0 multiplied by 064 mg/l doxycyline; MBC ranges were 2-8 mg/l azithromycin, 4-64 mg/l erythromycin and 0 multiplied by 5-8 mg/l doxycycline. Since azithromycin appears to be effective against C. trachomatis , clinical studies in sexually transmitted diseases are indicated.