The presence of Cutibacterium acnes on the skin of the shoulder after the use of benzoylperoxide

Rationale: Cutibacterium acnes (C. acnes) is one of the most frequent pathogens of infections after shoulder surgery. C. acnes colonization is greater in the shoulder epidermis compared to other regions of the body due to the high presence of sebaceous glands where C. acnes resides in. This bacterium can cause low-grade infections following shoulder surgery, which are difficult to diagnose and can lead to pain, stiffness and even failure of the prosthesis. Standard surgical skin disinfection and preparation in combination with intravenous prophylactic antibiotics do not seem to be effective on reducing the bacterial load of C. acnes, because they do not penetrate the membrane of the sebaceous glands. If a relatively simple preoperative intervention, such as application of a gel on the skin to be operated, can reduce the presence of C. acnes, this will probably lead to less postoperative infections. Consequently, it will improve the well-being of the patients and reduce additional health-care costs.

Objective: To evaluate if topical benzoyl peroxide reduces the presence of C. acnes on the skin of the shoulder compared to a topical placebo.

Study design and population: Double-blind randomised placebo-controlled trial including healthy human volunteers between 40-80 years old. Three baseline skin swabs will be taken to determine if C. acnes is present on the skin of the shoulder and patient characteristics will be gathered. Participants with C. acnes on the skin of the shoulder will be randomized into the benzoylperoxide or placebo group and are then requested to apply the gel 5 times during 2 days. Thereafter, three skin swabs will be taken to determine if C. acnes is present after the use of the gel (benzoylperoxide or placebo) and information about adverse events will be collected.

Topical benzoyl peroxide, applied on 5 consecutive moments by participants with positive baseline cultures for C. acnes, will reduce the number of positive skin cultures with 50% or more

T0: first appointment (baseline skin swabs, patient characteristics)
T1: second appointment (follow-up skin swabs, adverse events), approximately 3 weeks after T0.

5 times application of benzoylperoxide (Benzoylperoxide TEVA 50 MG/G, Hydrogel, Teva Nederland B.V. Haarlem, The Netherlands)

Placebo: Carbomeerwatergel 1% FNA, Hydrogel, Fagron NL B.V. Capelle aan den Ijssel, The Netherlands