Photodynamic therapy of red and blue lights on Malassezia pachydermatis: an in vitro study

In veterinary medicine, infection caused by Malassezia pachydermatis is spreading and necessity of alternative treatment is emphasized. Photodynamic therapy (PDT) is therapeutic method using specific spectrum of light with photosensitizer. In this study, applying PDT not only using red light which is used in human medicine commonly, but also using blue light into skin infection causative microorganism with photosensitizer, confirm the effect of PDT and possibility of being an alternative treatment. Four isolates of M. pachyderematis were collected from canine skin and used into this study. Light emitting diode with 495 nm, 625 nm spectrum was applied, and final concentration of δ-aminolevulinic acid (ALA), which is used as a photosensitizer, was adjusted into 20%. To confirm effectiveness of PDT, the number of colony forming unit was checked and variation of optical density values was measured. Antifungal effect of PDT on both spectrums was presented in all condition, and it makes best result when using blue light applied with ALA. Through outcome of this study, PDT using light in 465 nm, 625 nm wavelength combinations with ALA can interrupt proliferation of M. pachydermatis considerably. In consequence, PDT can be alterative treatment of canine Malassezia infection.