Background: Yeasts of the genus Malassezia are known as the microflora of human skin and that of many warm blooded animals; but the different Malassezia species can induce superficial skin infections. The purpose of the present study was to investigate the biochemical-physiological characteristics of Malassezia species isolated from pityriasis versicolor and seborrhoeic dermatitis patients and gain insight into the epidemiology and ecology of the species identified. Materials and methods: Twenty two pityriasis versicolor and seborrhoeic dermatitis outpatients at Razi Hospital of Tehran University were included in this study. The samples were cultured and identified for Malassezia spp. using the following criteria: morphological characteristics; growth on Dixon medium at different temperatures, growth on sabouraud's medim supplemented with tween 20, 40, 60, 80 and cremophore EL in diffusion test, esculin hydrolase and catalase screening, and pigment synthesis. Results: In 6 patients (27/3%), more than one Malassezia species was cultured. M. furfur was the prevalent species isolated from pityriasis versicolor either alone (44/4 %) or in combination with M. globosa or M. sympodialis (44/4 %); while M. globosa was most frequently isolated from seborrhoeic dermatitis either alone (38/5 %) or combination with M. furfur (7/7 %). Conclusion: We found different physiological characteristics of Malassezia isolates from all patients; likewise, it suggests that the geographical variations in the distribution of Malassezia species in PV and SD lesions may reflect climatic differences.

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