In vitro activity of clindamycin against Chlamydia trachomatis

Clindamycin hydrochloride was moderately active in vitro against Chlamydia trachomatis when it was added to the culture system 1 hr, but not 48 hr, after inoculation of test organisms. Clindamycin is almost as active in vitro against C. trachomatis as is erythromycin in vitro; this finding suggests that clindamycin might have clinically significant activity in vivo.