Background: To investigate the biochemical-physiological characteristics and genetic variations of Malassezia species isolated from pityriasis versicolor and seborrhoeic dermatitis patients. 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. by the conventional techniques based on the morphological, biochemical and physiological characteristics. Random amplification of polymorphic DNA polymerase chain reaction (RAPD-PCR) was applied for genetic variations of the isolates. Results: 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 %). The RAPD analysis among Malassezia isolates was counteracted from 238 amplified products in 81 separable positions and indicated that all Malassezia isolates were composed of nine genetically distant groups. Conclusion: We found different physiological characteristics and genetic variations of Malassezia isolates from all patients. Moreover, RAPD-PCR can be used as a powerful tool in epidemiological investigation of dermatological disorders associated with Malassezia species such as pityriasis versicolor and seborrhoeic dermatitis.

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