Antimicrobial photodynamic therapy with rose bengal acetate kills methicillin-resistant staphylococcus aureus and accelerates wound healing in a diabetic mouse model

aPDT can be strongly potentiated by the addition of potassium iodide (KI). Rose bengal acetate (RBAC) is easily taken up by cells and hydrolyzed to produce an active photosensitizer. Because KI is not taken up by microbial cells, it was of interest to see if RBAC-aPDT could also be potentiated by KI. We explored the antibacterial effect and mechanism of RBAC-mediated aPDT. RBAC-aPDT exhibited photoactivity against MRSA, Escherichia coli and Candida albicans. In addition, the combination of KI and RBAC could exert a synergistic bactericidal effect. RBAC led to the generation of large amounts of reactive oxygen species in the bacterium after irradiation, which caused DNA and protein degradation. Moreover, both RBAC-aPDT regimens accelerated the healing of MRSA-infected excisional wounds in diabetic mice. Therefore, RBDA-aPDT can kill Gram-positive/negative bacteria as well as fungal yeast, and that this killing can be strongly potentiated by the addition of KI.