Sanaz Aghaei Gharehbolagh - Department of Medical Mycology & Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Zahra Salehi - Department of Mycology, Pasteur Institute of Iran, Tehran ۱۳۱۶۴, Iran.
Setareh Agha Kuchak Afshari - Department of Medical Mycology & Parasitology, Faculty of Medicine, Kerman Medical University, Kerman, Iran.
Sassan Rezaie - Department of Medical Mycology & Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.

Background: Opportunistic lipophilic Malassezia yeasts are among Basidiomycota family of fungi and are among micro flora of human skin. In some situation, these commensal yeasts could be converted to opportunistic pathogens and can cause Pityriasis versicolor, saeboric dermatitis, folliculitis, atopic dermatitis. In this study, we investigated the possible effects of UV lights on Malassezia sympodialis (M. sympodialis) yeast. Furthermore, we study the possible changes in drug resistance pattern of this species before and after exposure as well as possible changes in gene regulations related to resistance and pathogenicity. Methods: The M. sympodialis yeasts have been isolated from the body surface of healthy individuals. The obtained yeasts were grown on Dixon Agar plates and were exposed under UVA (365 nm) and UVB (302 nm) sources separately, for 5, 20 and 30 minutes, then incubated at 32°C for 5 days. In vitro activity of KTC against M. sympodialis and a quantitative Real Time PCR was performed for evaluation of the antifungal susceptibility testing and expression level of MSY001_1493 and Malas13 genes after UV exposure. Results: M. sympodialis yeasts showed greater resistance (MIC90) when were exposed to UVA and UVB for 20 and 5 min, respectively. There were no differences between the MICs of samples which were exposed to the UV for 30 min in compares to the normal sample, without UV exposure. The expression levels of MSY001_1493 and Malas13 genes distinctly increased after 5 and 20 min (P<0.05). While the expression levels of mentioned genes haven t changed in M. sympodialis which were exposed to UVA and UVB for 30 min (P<0.05). Conclusions: The obtained results of the present study show the importance of proper duration of UV radiation on reduce drug susceptibility and progress towards pathogenicity of M. sympodialis. In addition, UV radiation could affect on related gene expression which could affect on the intensity of pathogenicity of this Malassezia species.

Ultraviolet Radiation; Antifungal Susceptibility Test; Malassezia sympodialis.