Efficacy of a photodynamic therapy protocol for the inactivation of Candida species

Abstract

The species of the Candida genus are responsible for a large part of cases of infections, with oral candidosis being highly prevalent. Considering the problems attributed to fungal resistance due to conventional treatments, alternative therapies for candidoses have been developed, among them photodynamic therapy (PDT). PTD protocols may be more easily assimilated into clinical practice if materials that have been approved for dental use are used. Therefore, in this in vitro study, the proposal is to evaluate the effectiveness of PDT for the inactivation of Candida albicans and Candida dubliniensis, two ATCC strains and two resistant to fluconazole, in their planktonic form. For this purpose, the following will be used: a concentration of 5% erythrosine (E), three doses of LED light in the blue wavelength (36, 108 or 180 J/cm2), and two pre-irradiation times (30 seconds or 1 minute). The cultures of planktonic and biofilm suspensions will be evaluated in the following manner: (L+E+), 5% erythrosine application followed by LED irradiation; (L-E+), erythrosine application only; (L+E-), saline application followed by irradiation; (L-E-) saline application only. The number of colony forming units (CFU/mL) of the microorganisms will be obtained after treatments. The Student's-t test will be used in comparison with a mean with a standard value, and in the comparison of two means, considering significance level of 5%.