Resumo

Introduction Photodynamic therapy has been originally developed for cancer treatment, but recently, it has been successfully employed against microorganisms, including fungi. Chromoblastomycosis is a subcutaneous fungal infection that is recalcitrant to conventional antifungal drug therapy. The treatment consists in prolonged use of conventional antifungal agents, surgical removal of the lesions or cryosurgery and recurrences are very frequent. The most frequent species involved are Foncecaea pedrosoi and Cladophialophora carrionii. Recently, patients with Chromoblastomycosis have been successfully treated with PDT. The present study aimed to verify the efficacy in vitro of PDT employing methylene blue as a photosensitizer and LED (InGaAl) as the light source. Material and Methods Methylene blue at the concentrations of 16, 32 and 64 Eg/mL and LED (InGalP) were employed for 15 minutes against spores of two isolates of Foncecaea pedrosoi and two isolates of Cladophialophora carrionii. A suspension of 106 spores was mixed with methilene blue in the concentrations cited above and let in the dark for 1 hour. Than LED was applied and the spores were plated on Sabouraud Dextrose agar and the number of colony forming units was counted after 7 to 10 days of incubation at 37°C. Results The PDT with methylene blue and LED was efficient in reducing the growth of all samples tested. The better results were obtained for the concentration of 32 Eg/ mL of methylene blue. Discussion PDT is a minimally invasive technique which has been successfully employed for the treatment of fungal infections. The present study together with previous works corroborates our hypothesis that photodynamic therapy can be an important tool to the treatment of chromoblastomycosis. PDT can be used either as isolate treatment or as adjutant therapy to conventional antifungal agents. The use of PDT might reduce the toxicity caused by the prolonged used of antifungal agents. Besides, the treatment is shortened and it could achieve a better adhesion to the treatment by patients. . Conclusion Samples of Foncecaea pedrosoi and Cladophialophora pedrosoi were killed by PDT when tested in vitro. PDT arises as a promising alternative for the treatment of this subcutaneous infection.