Synergistic activity of dispersin B and benzoyl peroxide against Cutibacterium acnes biofilms

Cutibacterium acnes has been implicated in the pathogenesis of acne vulgaris. C. acnes forms biofilms which may contribute to host colonization and antimicrobial resistance. Poly-N-acetylglucosamine (PNAG) is an exopolysaccharide that mediates C. acnes biofilm formation. In this study we investigated the ability of the PNAG-degrading enzyme dispersin B to sensitize C. acnes biofilms to killing by the anti-acne agent benzoyl peroxide (BPO). C. acnes biofilms were cultured aerobically in glass tubes in the presence of Staphylococcus epidermidis which has been shown to stimulate C. acnes biofilm formation. Biofilms were treated with 5-80 g/ml dispersin B and/or 0.1-2.5% BPO. Treatment of biofilms with dispersin B or BPO alone resulted in a 1-2 log reduction C. acnes CFUs, whereas treatment of biofilms with dispersin B followed by BPO resulted in a >6 log reduction in C. acnes CFUs. Concentrations as low as 5 g/ml dispersin B and 0.5% BPO efficiently eradicated C. acnes from the dual-species biofilm. Our findings confirm that PNAG protects C. acnes from benzoyl peroxide killing and demonstrate that dispersin B and BPO act synergistically to kill C. acnes biofilm cells. Dispersin B may be a useful adjunct to BPO for the treatment and prevention of acne.