Efficacy of topical benzoyl peroxide on the reduction of Propionibacterium acnes during shoulder surgery.

BACKGROUND Propionibacterium acnes infection is a significant problem after shoulder surgery. Residual P. acnes is found on the skin up to 29% of the time immediately after surgical skin preparation and in 70% of dermal biopsy specimens. These residual bacteria may be a source for infection. Identifying more ideal skin preparation may help reduce the risk of infection. The purpose of this study was to evaluate the effect that topical benzoyl peroxide (BPO), with chlorhexidine skin preparation, would have on the presence of P. acnes cultured at the time of shoulder surgery. We hypothesized that adding topical BPO to our skin preparation would reduce the number of positive P. acnes cultures identified during surgery. METHODS Fifty patients undergoing first-time shoulder surgery were treated with topical 5% BPO cream 48 hours before surgery. After skin preparation, 13 samples per subject were obtained. Cultures were held for 14 days. RESULTS Fifty patients underwent arthroscopic shoulder surgery; 650 culture specimens were obtained. The skin was positive at the initiation of surgery in 6% of cases. Tissue samples were positive in 6%. The skin was positive in 10% at the end of surgery. None of these rates of positive culture were different from the 4% rate observed with a control swab. CONCLUSION Application of BPO is an effective way to reduce P. acnes on skin at the beginning and, importantly, at the end of a surgical procedure. This may result in a lower risk for postoperative infection.