Identification of Malassezia species from Tunisian patients with pityriasis versicolor and normal subjects

Abstract

The genus Malassezia (Pityrosporum), recognized as a member of microbiological flora of the skin in humans and warm-blooded animals, has been recently revised to include 10 Malassezia species. The aim of the study was the isolation, identification and analysis of Malassezia species distribution in skin of healthy volunteers and lesions of pityriasis versicolor (PV). Specimens were taken from 100 patients with PV and 30 healthy volunteers. Cultures were made in modified Dixon agar medium and the isolates were identified by morphological and physiological methods: macroscopy, microscopy, catalase, beta-glucosidase and lipid assimilation tests. Malassezia globosa was the predominant species in lesional skin of PV (65%). It was isolated alone in 47% of cases and associated in 18% with M. furfur (13%) or M. sympodialis (5%). In healthy skin M. globosa was found alone in 7.77% and associated in 15.54%, respectively, with M. furfur (4.44%), M. sympodialis (4.44%), M. restricta (3.33%) and M. slooffiae (1.11%). From these findings it was suggested that M. globosa presents the main species implicated in the pathogenicity of PV and M. furfur as the second agent of importance.