title: Photodynamic antimicrobial chemotherapy (PACT) inhibits biofilm formation by Candida albicans, increasing both ROS production and membrane permeability.
abstract: The opportunistic fungal Candida albicans is able to produce both superficial and systemic infections in immunocompromised patients. Photodynamic antimicrobial chemotherapy (PACT) is a process that combines visible light and a photosensitizer, producing reactive oxygen species (ROS) that can kill the treated cells and has been presented as a potential antimicrobial therapy. In this work, we study the effects of PACT, using toluidine blue (TB) as a photosensitizer drug, on ROS production and cell damage and the ability of C. albicans to form biofilm. A significant decrease was observed in the cell growth after PACT in a TB concentration-dependent manner. This effect was dependent on the incubation time after PACT. In addition, an increase in both the ROS production and cell permeability, after PACT, in a TB concentration-dependent manner was observed. PACT, using 0.1 mg/ml TB was able to reduce biofilm formation in 30, 50, and 62%, in cells submitted to incubation times of 1, 2, and 3 h, respectively. These results suggested that PACT, using TB, is able to decrease both growth and biofilm formation by C. albicans, possibly by a mechanism evolving both ROS production and the increase in the cell permeability.
authors.affiliation: Instituto de Pesquisa e Desenvolvimento (IP&D), Universidade do Vale do Paraíba (UNIVAP), Av. Shishima Hifumi, 2911, 12244-000, São José dos Campos, São Paulo, Brazil.
authors.forename: Isabela Bueno
authors.initials: IB
authors.lastname: Rosseti
authors.forename: Luciene Reginato
authors.initials: LR
authors.lastname: Chagas
authors.forename: Maricilia Silva
authors.initials: MS
authors.lastname: Costa
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology; D018441:Biofilms / Q000187:drug effects* / Q000528:radiation effects; D002176:Candida albicans / Q000187:drug effects* / Q000502:physiology / Q000528:radiation effects; D002177:Candidiasis / Q000188:drug therapy; D002463:Cell Membrane Permeability / Q000187:drug effects* / Q000528:radiation effects; D006801:Humans; D008027:Light; D008826:Microbial Sensitivity Tests; D010539:Permeability; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D014048:Tolonium Chloride / Q000494:pharmacology
chemical_list: D000890:Anti-Infective Agents; D017319:Photosensitizing Agents; D017382:Reactive Oxygen Species; D014048:Tolonium Chloride