Photodynamic inactivation of four Candida species induced by photogem®

Abstract

This study evaluated the in vitro susceptibility of C. albicans, C. dubliniensis, C. tropicalis and C. krusei to photodynamic therapy (PDT) induced by Photogem®and light emitted diode (LED). Suspensions of each Candida strain were treated with three photosensitizer (PS) concentrations (10, 25 and 50 mg/L) and exposed to 18, 25.5 and 37.5 J/cm2 LED light fluences (λ ~ 455 nm). Control suspensions were treated only with PS concentrations, only exposed to the LED light fluences or not exposed to LED light or PS. Sixteen experimental conditions were obtained and each condition was repeated three times. From each sample, serial dilutions were obtained and aliquots were plated on Sabouraud Dextrose Agar. After incubation of plates (37 °C for 48 hours), colonies were counted (cfu/mL) and the data were statistically analyzed by ANOVA and the Tukey test (α=0.05). Complete killing of C. albicans was observed after 18 J/cm2 in association with 50 mg/L of PS. C. dubliniensis were inactivated after 18 J/cm2 using 25 mg/L of PS. The inactivation of C. tropicalis was observed after photosensitization with 25 mg/L and subsequent illumination at 25.5 J/cm2. For C. krusei, none of the associations between PS and light resulted in complete killing of this species. PDT proved to be effective for the inactivation of C. albicans, C. dubliniensis and C. tropicalis. In addition, reduction in the viability of C. krusei was achieved with some of the PS and light associations.

Mixed biofilms formed by C. albicans and non-albicans species: a study of microbial interactions

“…Nonetheless, non-albicans species, such as Candida glabrata, Candida tropicalis and Candida krusei, are also frequently associated with the development of infections. 25 Candida albicans sometimes exists in a mixture with other microbial species in this environment. 26 The virulence of C. albicans may be influenced not only by its own properties but also by its interactions with cohabitating oral microorganisms.…”

Photobiological characteristics of chlorophyll a derivatives as microbial PDT agents

“…[34][35][36] The PDT inactivation experiments with Candida albicans were also performed to evaluate the effect of these PSs in a fungus cell, as it has a different cell wall when compared to bacteria. 37 We evaluated the PDT activity of both PSs at 20 and 30 μg mL Previous studies have reported the inactivation of Candida albicans with PDT using Photogem, 37 which presents the same complete inhibition with 50 μg mL −1 and a fluence of…”

Efficacy of Photogem® (Hematoporphyrin Derivative) as a Photoactivatable Larvicide against Aedes aegypti (Diptera: Culicidae) Larvae

“…aegypti. PG, which has been widely used in photodynamic therapy for the treatment of cancer and in photodynamic inactivation of pathogenic microorganisms (fungi and bacteria) [21][22][23][24] has shown high potential for the elimination of Ae. aegypti larvae.…”