title: In Vitro Antimicrobial Photodynamic Therapy Against Trichophyton mentagrophytes Using New Methylene Blue as the Photosensitizer.
abstract: OBJECTIVE
  Antimicrobial photodynamic therapy combines the use of a photosensitizing drug with light and oxygen to eradicate pathogens. Trichophyton mentagrophytes is a dermatophytic fungus able to invade the skin and keratinized tissues. We have investigated the use of new methylene blue as the photosensitizing agent for antimicrobial photodynamic therapy to produce the in vitro inactivation of T mentagrophytes.
  
  
  METHODS
  A full factorial design was employed to optimize the parameters for photoinactivation of the dermatophyte. The parameters studied were new methylene blue concentration, contact time between the photosensitizing agent and the fungus prior to light treatment, and the fluence of red light (wavelength, 620-645nm) applied.
  
  
  RESULTS
  The minimum concentration of new methylene blue necessary to induce the death of all T. mentagrophytes cells in the initial suspension (approximate concentration, 106colony forming units per milliliter) was 50μM for a fluence of 81J/cm2after a contact time of 10minutes with the photosensitizing-agent. Increasing the concentration to 100μM allowed the fluence to be decreased to 9J/cm2.
  
  
  CONCLUSIONS
  Comparison of our data with other published data shows that the susceptibility of T. mentagrophytes to antimicrobial photodynamic therapy with new methylene blue is strain-dependent. New methylene blue is a photosensitizing agent that should be considered for the treatment of fungal skin infections caused by this dermatophyte.
authors.affiliation: Institut Quimic de Sarrià, Universitat Ramon Llull, Barcelona, España.
authors.forename: P
authors.initials: P
authors.lastname: López-Chicón
authors.affiliation: Institut Quimic de Sarrià, Universitat Ramon Llull, Barcelona, España.
authors.forename: Ò
authors.initials: Ò
authors.lastname: Gulías
authors.affiliation: Institut Quimic de Sarrià, Universitat Ramon Llull, Barcelona, España.
authors.forename: S
authors.initials: S
authors.lastname: Nonell
authors.affiliation: Institut Quimic de Sarrià, Universitat Ramon Llull, Barcelona, España. Electronic address: montserrat.agut@iqs.url.edu.
authors.forename: M
authors.initials: M
authors.lastname: Agut
mesh_terms: D004353:Drug Evaluation, Preclinical; D006801:Humans; D066298:In Vitro Techniques; D008751:Methylene Blue / Q000031:analogs & derivatives* / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D010777:Photochemistry; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology*; D013535:Suspensions; D014249:Trichophyton / Q000187:drug effects* / Q000528:radiation effects
chemical_list: D017319:Photosensitizing Agents; D013535:Suspensions; C035184:new methylene blue; D008751:Methylene Blue
keywords: Antimicrobial photodynamic therapy; New methylene blue; Nuevo azul de metileno; Terapia fotodinámica antimicrobiana; Trichophyton mentagrophytes