Distribution of Malassezia species in Mexican seborrheic dermatitis patients

Yeasts of the Malassezia genus are linked to seborrheic dermatitis (SD) in humans; however, etiological species causing this disease can vary according to their geographical location. M. globosa and M. restricta are the most often isolated microorganisms and can be found in the skin of patients with SD. Nevertheless, species identification by molecular methods and the relationship among etiological agents and the clinical severity of the disease have not been determined in Mexican patients. The goal of this study was to analyze the prevalence of Malassezia species in the skin of SD patients by molecular methods in order to establish their distribution according to the severity of the disease in Monterrey, Nuevo Leon, Mexico. Skin samples from patients with SD (n = 60) were obtained by scraping and were cultured on modified Dixon agar. The Malassezia colonies were identified by amplification of the D1/D2 regions of 26S rDNA by polymerase chain reaction (PCR) and subsequent sequencing and BLAST analysis in GenBank. The positive Malassezia culture rate was 48.3%. The most commonly isolated species were Malassezia furfur (20%), Malassezia globosa (16.7%), Malassezia sympodialis (6.7%), Malassezia restricta (3.3%) and Malassezia slooffiae (1.7%). No significant difference was found in the distribution of Malassezia species according to disease severity. Key words: Seborrheic dermatitis, Malassezia, LSU rDNA D1/D2, yeasts, Malassezia furfur; M. globosa.