Effectiveness of topically applied antibiotics on anaerobic bacteria in the pilo-sebaceous duct.

An unspecific cream vehicle containing 1% erythromycin base was applied once a day for 10 days to one side of the forehead of 16 healthy subjects and the same vehicle without the active agent to the other side. Using the same procedure a solution containing 1.19% clindamycin phosphate (corresponding to 1% clindamycin base) and the corresponding unspecific vehicle was administered to another group of 17 healthy males. Prior to the treatment and after the end bacteria were obtained from the pilosebaceous ducts by means of a special sampling technique. Both ointments containing the antibiotics lead to a significant reduction of the bacterial growth in the pilosebaceous ducts regardless of whether evaluation is made of the total bacterial count or of Propionibacteria. Thus, it could be demonstrated that topical application enables some antibiotics to penetrate into the pilosebaceous duct in an adequate concentration to ensure antibacterial effectiveness if a suitable vehicle is used.