Resumo

Malassezia yeasts are part of the resident human skin microbiota, although have also been associated with skin diseases such as dandruff and seborrheic dermatitis (D/SD). The role they play in the development of the symptoms is still unclear, nor is it apparent why these yeasts are pathogenic for some individuals and not for others. In this context, this work aims to compare Malassezia microbiota in healthy subjects and in patients with D/SD. Five healthy individuals and eight patients were analyzed (3 severe and 5 mild D/SD). Scalp samples were collected using sterile cotton swabs. A fragment comprising 5.8/ITS2 ribosomal DNA was amplified by PCR using Malassezia-specific primers, and cloned into bacterial vectors. Clone libraries were analyzed by RFLP and sequencing. Malassezia microbiotas from different samples were compared using similarity analysis such as Clustering, SIMPER (SIMilarity PERcentages) and MDS (MultiDimensional Scaling). Phylogenetic analyses were also performed. Only three species were found (M. globosa, M. restricta and M. dermatis), contrasting with previous data obtained in different countries. M. restricta was detected in all samples, being the most abundant species in 8 out of 13 samples, followed by M. globosa (detected in 11 samples). Different intra-specific patterns were identified. Sequencing data and phylogenetic analyses indicate a possible new Malassezia species, which was found in 7 samples, and was the most abundant organism in 3 of them. Moreover, two uncharacterized phylotypes previously reported were also detected in our study. Similarity analysis revealed that Malassezia communities were clustered into different groups, with no significant dichotomy between samples from healthy and diseased subjects. Our data suggests that Malassezia microbiota is host-specific and indicates particular characteristics from the analyzed population, including a potential new species found in the majority of the samples. Thus far there is a limited amount of data available regarding the skin microbiota from Brazilian subjects. Our findings reveal differences in comparison with data from other countries. The characterization of Malassezia sp. in the Brazilian population has the potential to contribute to the elucidation of the diversity of skin microbiota in health and disease, and to clarify the role of these fungi in skin disorders.