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In vitro studies on the antifungal effect of PUVA
Abstract:
The effect of PUVA therapy upon 12 dermatophyte strains, 3 of Candida albicans, and 4 of mould fungi was evaluated by the agar dilution method on Sabouraud agar. 8-MOP, 30 microgram/ml medium plus UVA, 4 Joule/cm2 proved to be fungicidal dose to all the strains studied, with the exception of three of the mould fungi. For dematophytes and Candida albicans the MIC was between 1 and 3 microgram, 8-MOP plus UVA, 4 J; and 3 microgram when the UVA dose was reduced to 1--2 J. For mould fungi it was higher. The MFC varied within the range 2 to 30 microgram, when the UVA dose was fixed at 4 J. It reached 16 J when the dose of 8-MOP was kept at 4 microgram. The wide range in the MFC of the dermatophytes could be due to resistant colonies. 8-MOP alone had a distinctly inhibitory effect upon dermatophytes, but not upon Candida albicans or mould fungi.
Insights
Photochemotherapy using 8-methoxypsoralen (8-MOP) with ultraviolet A (UVA) light is fungicidal against dermatophytes and Candida albicans. This combination therapy shows potential for treating fungal infections, though some mould fungi exhibit resistance.
Area of Science:
- Dermatology
- Photobiology
- Mycology
Background:
- Fungal infections caused by dermatophytes, Candida albicans, and moulds pose significant health challenges.
- Photochemotherapy, specifically PUVA (psoralen plus ultraviolet A), is a known treatment modality for various skin conditions.
- The antifungal efficacy of PUVA therapy against common human fungal pathogens remains an area for detailed investigation.
Purpose of the Study:
- To evaluate the in vitro fungicidal and fungistatic effects of PUVA therapy on clinically relevant fungal strains.
- To determine the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of 8-methoxypsoralen (8-MOP) combined with UVA radiation.
- To compare the efficacy of PUVA therapy against dermatophytes, Candida albicans, and various mould fungi.
Main Methods:
- The agar dilution method was employed using Sabouraud agar medium.
- Standardized fungal strains, including 12 dermatophytes, 3 Candida albicans, and 4 mould fungi, were tested.
- Varying concentrations of 8-MOP (8-methoxypsoralen) were combined with specific doses of UVA radiation (4 J/cm² and 1-2 J/cm²).
Main Results:
- A dose of 30 µg/ml 8-MOP plus 4 J/cm² UVA demonstrated fungicidal activity against all tested dermatophyte and Candida albicans strains.
- Three mould fungi strains showed resistance to the fungicidal effects of 8-MOP and UVA combination.
- Minimum Inhibitory Concentrations (MICs) for dermatophytes and Candida albicans ranged from 1-3 µg/ml 8-MOP with 4 J/cm² UVA, and 3 µg/ml with 1-2 J/cm² UVA.
- Minimum Fungicidal Concentrations (MFCs) varied from 2-30 µg/ml 8-MOP at 4 J/cm² UVA, and reached 16 J/cm² UVA with 4 µg/ml 8-MOP.
- 8-MOP alone exhibited inhibitory effects on dermatophytes but not on Candida albicans or mould fungi.
Conclusions:
- PUVA therapy, specifically 8-MOP combined with adequate UVA dosage, is a potent fungicidal agent against dermatophytes and Candida albicans.
- The study highlights potential resistance in certain mould fungi, indicating the need for further investigation into treatment strategies for these pathogens.
- The findings support the consideration of PUVA therapy as a viable treatment option for specific superficial fungal infections.