In vitro fungicidal effects of methylene blue at 625-nm

The aim of the study is to confirm the effectiveness of photodynamic therapy (PDT) as a significant inhibitor of Trichophyton rubrum (T. rubrum) and to determine the most appropriate dose and rate of delivery. Trichophyton rubrum is the most common dermatophyte worldwide, responsible for the majority of superficial fungal infections. The traditional treatment of T. rubrum has known adverse effects. An alternative treatment is warranted. Photosensitised T. rubrum specimens were treated with 625-nm light at doses of 3, 12, 24, 40 and 60 J/cm² . Colony counts were performed and compared to untreated controls. Doses of 24, 40 and 60 J/cm² all produced kill rates of over 94%. A lower rate of delivery (7.80 mW/cm² ) was shown to be a greater inhibitor of T. rubrum than a higher rate of delivery (120 mW/cm² ). Photodynamic therapy with methylene blue (MB) at 625 nm using a low rate of delivery at doses of 24, 40 and 60 J/cm² is an effective inhibitor of T. rubrum. A rate of delivery of 7.80 mW/cm² is a significantly greater inhibitor of T. rubrum than a rate of 120 mW/cm² when applying 625-nm light in PDT using MB.