Effect of erythrosine- and LED-mediated photodynamic therapy on buccal candidiasis infection of immunosuppressed mice and Candida albicans adherence to buccal epithelial cells.

OBJECTIVE: This study evaluated the effects of photodynamic therapy (PDT) on buccal candidiasis in mice and on the adherence of yeast to buccal epithelial cells (BECs) in vitro. STUDY DESIGN: A total of 56 immunosuppressed mice with buccal candidiasis were subjected to PDT, consisting of treatment with erythrosine (400 µmol/L) followed by exposure to a green LED (14.34 J cm(-2)). After treatment, the yeasts recovered from the mice were quantified (CFU/mL) and analyzed for the effects of PDT on their adherence to BECs. The data were analyzed using ANOVA, the Tukey test, Kruskal-Wallis test and Student t test. RESULTS: PDT significantly reduced the amount of yeast present in the lesions by 0.73 log(10) (P = .018) and reduced C. albicans adherence to BECs by 35% without damaging adjacent tissues (P = .045). CONCLUSIONS: Photodynamic therapy exhibited antifungal effects against C. albicans biofilms formed in vivo and reduced the capacity of C. albicans to adhere to BECs in vitro.

Susceptibility of Candida albicans and Candida dubliniensis to erythrosine- and LED-mediated photodynamic therapy.

The effect of erythrosine- and LED-mediated photodynamic therapy (PDT) on planktonic cultures and biofilms of Candida albicans and Candida dubliniensis was evaluated. Planktonic cultures of standardized suspensions (10(6)cells/mL) of C. albicans and C. dubliniensis were treated with erythrosine concentrations of 0.39-200 µM and LEDs in a 96-well microtiter plate. Biofilms formed by C. albicans and C. dubliniensis in the bottom of a 96-well microtiter plate were treated with 400 µM erythrosine and LEDs. After PDT, the biofilms were analysed by scanning electron microscopy (SEM). The antimicrobial effect of PDT against planktonic cultures and biofilms was verified by counting colony-forming units (CFU/mL), and the data were submitted to analysis of variance and the Tukey test (P<0.05). C. albicans and C. dubliniensis were not detectable after PDT of planktonic cultures with erythrosine concentrations of 3.12 µM or higher. The CFU/mL values obtained from biofilms were reduced 0.74 log(10) for C. albicans and 0.21 log(10) for C. dubliniensis. SEM revealed a decrease in the quantity of yeasts and hyphae in the biofilm after PDT. In conclusion, C. albicans and C. dubliniensis were susceptible to erythrosine- and LED-mediated PDT, but the biofilms of both Candida species were more resistant than their planktonic counterparts.