Species of Malassezia associated with various dermatoses and healthy skin in the Mexican population

At the present, eight Malassezia species have been described and their distribution in normal skin and in several skin diseases appears variable. The aim of the present study was to determine the frequency and distribution of Malassezia species in patients with psoriasis, seborrhoeic dermatitis and pityriasis versicolor attended in a Hospital from Mexico City, in addition to a healthy individual group. Scales of abnormal and healthy skin were grown in modified Dixon agar and the species identification was performed by macroscopic and microscopic features; by catalase and urease reaction; growth at 32, 37 and 40 degrees C; and Tween 20, 40, 60 and 80 assimilation. The cultures from 63 persons were included: forty six patients (20 psoriasis, 15 seborrhoeic dermatitis, 11 pityriasis versicolor) and 17 healthy individuals (external auditory canal). A total of 96 isolates were obtained. The more frequently isolated species were: M. sympodialis (38.2%) and M. furfur (26.5%) in psoriasis; M. sympodialis (38.5%) and M. slooffiae (34.6%) in seborrhoeic dermatitis; M. globosa (46.7%) and M. sympodialis (26.7%) in pityriasis versicolor; and M. restricta (47.6%) and M. globosa (23.8%) in normal skin. The number of isolates, the species diversity and association were higher in the patients group than in the healthy individuals group.