Phylogenetic analysis reveals unexplored fungal diversity on skin

Abstract

Despite recent advances, to date there is not full knowledge of microbial diversity inhabiting various organs of human body. Skin harbors a complex microbiome that might affect our health positively and negatively. Fungal communities from skin are dominated by Malassezia yeasts. Traditionally, they were thought to be causative agents of skin diseases; however, their role is controversial, and the possible implication of specific species and subtypes remains unclear. Previously, we have conducted two fungal community surveys in healthy skin and dandruff/sebohrreic dermatitis, and have detected prevalent Malassezia organisms that could not be assigned to any known species. The usage of distinct ITS rDNA regions did not allow sequence comparison between studies. Here we report molecular characterization and phylogenetic analysis of unidentified Malassezia organisms, aiming to increase knowledge in fungal microbiome from skin. Findings suggested that a highly prevalent organism might belong to a novel Malassezia species. Results also revealed uncertain taxonomic assignments, even in the case of accepted species. Correct assignment of species and intraspecific variants is relevant considering that specific taxa might be directly involved in disease development. Despite high prevalence, organisms might have remained undiscovered due to difficulties in culturing Malassezia. Challenges and future perspectives for skin fungal microbiome studies are discussed. We address issues to be overcome for unraveling the complete skin microbial diversity and its relation to health and disease.