Effectiveness of curcumin-based antimicrobial photodynamic therapy against Staphylococcus aureus

Purpose: This study investigated the effectiveness of curcumin-based antimicrobial photodynamic therapy (aPDT) against Staphylococcus aureus (S. aureus), the causative agent of ventilator-associated pneumonia.Methods: Curcumin was added to S. aureus culture medium at concentrations of 25, 2.5, and 0.25 mu M. After 60 min (20-25 degrees C), each culture was irradiated for 1 and 3 min, and viable bacteria were counted. Curcumin (25 mu M) was also added to a bacterial suspension with D-mannitol and sodium azide; microbial counts were determined after irradiation for 3 min.Results: S. aureus was significantly reduced in the 1-min (P = 0.043) and 3-min (P = 0.011) irradiation groups in comparison to the 0-min irradiation group with 25 mu M curcumin. No significant differences were observed between the curcumin alone group and the curcumin plus D-mannitol or sodium azide group.Conclusion: The findings of this study indicate that prolonged exposure (>= 1 min) of S. aureus to LED in 25 mu M curcumin solution induces cell wall injury. Curcumin-based aPDT as an adjunct to conventional oral care, employing existing dentistry equipment, offers a promising approach that does not rely on antimicrobial drugs or allows the emergence of resistant bacterial strains. This suggests its potential role in future strategies aimed at preventing ventilator-associated pneumonia.