<i>Malassezia</i> Intra-Specific Diversity and Potentially New Species in the Skin Microbiota from Brazilian Healthy Subjects and Seborrheic Dermatitis Patients

<div><p><i>Malassezia</i> yeasts are part of the resident cutaneous microbiota, and are also associated with skin diseases such as seborrheic dermatitis (SD). The role these fungi play in skin diseases and why they are pathogenic for only some individuals remain unclear. This study aimed to characterize <i>Malassezia</i> microbiota from different body sites in healthy and SD subjects from Brazil. Scalp and forehead samples from healthy, mild SD and severe SD subjects were collected. Non-scalp lesions from severe SD patients were also sampled. 5.8S rDNA/ITS2 amplicons from <i>Malassezia</i> sp. were analyzed by RFLP and sequencing. Results indicate that <i>Malassezia</i> microbiota did not group according to health condition or body area. Phylogenetic analysis revealed that three groups of sequences did not cluster together with any formally described species, suggesting that they might belong to potential new species. One of them was found in high proportions in scalp samples. A large variety of <i>Malassezia</i> subtypes were detected, indicating intra-specific diversity. Higher <i>M. globosa</i> proportions were found in non-scalp lesions from severe SD subjects compared with other areas, suggesting closer association of this species with SD lesions from areas other than scalp. Our results show the first panorama of <i>Malassezia</i> microbiota in Brazilian subjects using molecular techniques and provide new perspectives for further studies to elucidate the association between <i>Malassezia</i> microbiota and skin diseases.</p></div

<i>Malassezia</i> subtype communities in 32 skin samples from healthy and SD subjects.

<p>(A) Proportion of <i>Malassezia</i> subtypes. (B) Clustering analysis of <i>Malassezia</i> microbiota. Solid black lines represent clusters significant at 95% according to Simprof test. Sample code: P: SD patient; H: healthy; S: scalp; F: forehead; L: non-scalp lesion sites.</p

<i>Malassezia</i> phylogenetic tree.

<p>Maximum Likelihood phylogenetic tree based on 5.8S/ITS2 rDNA sequences from <i>Malassezia</i> sp. 5.8S/ITS2 rDNA sequences are available for 12 <i>Malassezia</i> species. Potential new <i>Malassezia</i> species found in this study are highlighted. Bootstrap values > 50% are shown. Codes between parentheses correspond to Genbank accession numbers. Numbers between brackets represent the number of <i>Malassezia</i> species clones by body site.</p

Restriction digestion steps.

<p>Digestion step sequence for <i>Malassezia</i> species identification and detection of intra-specific polymorphisms.</p

Multi Dimensional Scaling of <i>Malassezia</i> microbiota at subtype level in 32 skin samples from healthy subjects and SD patients.

<p>(A) Similarity between samples highlighting health condition specifying severity; (B) health condition not specifying severity; (C) body site and (D) subjects. (E) Sample diversity. Circle diameter is proportional to the Shannon-Weaver index. Bubble size scale indicates the relative diversity, with the smallest diversity (P14-S) indexed as 1. (F) Mean diversity based on Shannon-Weaver diversity indexed by body site. Student’s T-test with bars representing Mean ± SEM. * p < 0.05. Sample code: P: SD patient; H: healthy; S: scalp; F: forehead; L: non-scalp lesion sites.</p