Photodynamic inactivation of the dermatophyte Trichophyton rubrum

Area of Science:

• Dermatology
• Mycology
• Photochemistry

Background:

• Superficial mycoses, such as tinea, are globally prevalent infectious diseases.
• Current treatments for dermatophyte infections face limitations including high recurrence rates and prolonged treatment durations.
• Dermatophytes, like Trichophyton rubrum, utilize keratin for growth, causing skin, hair, and nail infections.

Purpose of the Study:

• To investigate the efficacy of photodynamic treatment (PDT) as a novel therapeutic approach against the dermatophyte Trichophyton rubrum.
• To evaluate and compare the antifungal activity of various photosensitizers, including novel porphyrins, against T. rubrum.

Main Methods:

• Trichophyton rubrum was cultured in suspension and subjected to photodynamic treatment using different photosensitizers.
• Photosensitizers evaluated included deuteroporphyrin monomethylester (DP mme), Sylsens B, deuteroporphyrin, hematoporphyrin, Photofrin, and phthalocyanines.
• Broadband white light was used for PDT, and the photodynamic efficacy was compared with dark toxicity.

Main Results:

• Both Sylsens B and DP mme demonstrated effective photodynamic killing of T. rubrum.
• Sylsens B exhibited the highest efficacy among the tested porphyrins, with no dark toxicity observed.
• Other photosensitizers like phthalocyanines and Photofrin showed fungistatic effects, while deuteroporphyrin and hematoporphyrin also induced photodynamic killing.
• Concentration-dependent uptake of Sylsens B and DP mme by T. rubrum was observed.

Conclusions:

• Photodynamic treatment represents a novel and effective strategy for combating dermatophyte infections.
• Sylsens B and DP mme are promising photosensitizers for PDT, showing potent antifungal activity against T. rubrum.
• Further development of Sylsens B in a suitable formulation could lead to new treatments for various forms of tinea.