The Antibiotic Susceptibility of Propionibacterium acnes: A 15‐year Bacteriological Study and Retrospective Evaluation

Abstract Propionibacterium acnes strains were isolated from the comedones of 46 acne patients, and their susceptibilities to penicillin G, ampicillin, erythromycin, clindamycin, tetracycline, doxycycline, minocycline, cephalexin and gentamycin were studied by examining their minimum inhibitory concentrations. Two additional standard strains were included in the study. In the results, differing antibiotic susceptibilities were found, and P. acnes strains were the most sensitive to erythromycin and clindamycin, followed by ampicillin and minocycline. The highest levels of resistance were observed against clindamycin, erythromycin and tetracycline. Non‐resistant strains were detected only against minocycline. A comparison of these results with others obtained by similar studies in our department during the last 15 years showed a progressive tendency toward antibiotic resistance for Propionibacterium acnes, probably related to the systemic administration of antibiotics for the treatment of bacterial infections other than acne.