Clinical efficacy of topical clindamycin phosphate and azelaic acid on acne vulgaris and emergence of resistant coagulase-negative staphylococci

In this study, the uses of topical clindamycin phosphate and azelaic acid were compared from point of clinical efficacy and emergence of resistant coagulase-negative staphylococci (CNS). Each group contained 20 patients. Pre- and post-treatment acne grades and comparison of two groups were evaluated by using the Wilcoxon and Spearman statistical techniques. The sensitivity of CNS to azelaic acid and to clindamycin phosphate were searched by microbroth dilution technique. Azelaic acid was found more effective in reducing acne grade. Eleven CNS strains were found resistant to clindamycin phosphate before treatment. After 8 weeks of therapy with topical clindamycin phosphate 18 of 20 CNS strains were resistant to this agent. No difference was detected for the MIC (minimal inhibitory concentration) values of CNS before and after topical azelaic acid treatment.