Study of solar photosensitization processes on dermatophytic fungi
Ouf, S.A.; Abdel-Kader, M.H.; Shokeir, H.A.; El-Adly, A.A.
Acta Microbiologica Polonica 52(1): 65-79
2003
ISSN/ISBN: 0137-1320 PMID: 12916729 Document Number: 555618
The antifungal activity of solar simulator was evaluated in presence of haematoporphyrin derivative (HPD), methylene blue (MB) and toluidine blue O (TBO) as photosensitizers. Seven dermatophytes were used as test fungi. The solar simulator at fluence rate 400 W/m2 for 30 minutes induced marked inhibition of spore germination of the photosensitized fungi. The rate of inhibition varied according to fungal species and concentration of the photosensitizer. There was an increase in percentage inhibition of spore germination as the concentration of HPD or MB increased. Complete inhibition of spore germination of Trichophyton verrucosum, T. mentagrophytes and Microsporum canis was induced when these species were pretreated with 10-3 M of HPD or MB before irradiation. Epidermophyton floccosum, T. rubrum, M. gypseum and T. violaceum were less sensitive to irradiation when pretreated with HPD or MB. On contrary, the maximum reduction in percentage spore germination was induced at the lowest concentration (10-7 M) of TBO. The tested dermatophytes were mostly capable of producing different enzymes (keratinase, phosphatases , amylase and lipase). The separate application of radiation or photosensitizer was ineffective or exerted slight inhibition on enzyme production. However, the activity of the enzymes was drastically inhibited when the fungi were irradiated after their treatment with photosensitizer. T. verrucosum and T. mentagrophytes were the most sensitive. In guineapigs experimentally infected with T. verrucosum, T. mentagrophytes or M. canis, solar simulator radiation successfully treated MB-photosensitized guineapigs. The percentage of recovery reached 100% in some treatments.