Study of the distribution of Malassezia species in patients with pityriasis versicolor and healthy individuals in Tehran, Iran

BACKGROUND: Pityriasis versicolor is a superficial infection of the stratum corneum which caused by a group of yeasts formerly named pityrosporium. The taxonomy of these lipophilic yeasts has recently been modified and includes seven species referred as Malassezia. The aim of this study is to compare the distribution of Malassezia species isolated from pityriasis versicolor lesions and those isolated from healthy skins. METHODS: Differentiation of all malassezia species performed using morphological features and physiological test including catalase reaction, Tween assimilation test and splitting of esculin. RESULTS: In pityriasis versicolor lesions, the most frequently isolated species was M. globosa (53.3%), followed by M. furfur (25.3%), M. sympodialis(9.3%), M. obtusa (8.1%) and M. slooffiae (4.0%). The most frequently isolated species in the skin of healthy individuals were M. globosa, M. sympodialis, M. furfur, M. sloofiae and M. restricta which respectively made up 41.7%, 25.0%, 23.3%, 6.7% and 3.3% of the isolated species. CONCLUSIONS: According to our data, M. globosa was the most prevalent species in the skin of healthy individuals which recovered only in the yeast form. However, the Mycelial form of M. globosa was isolated as the dominant species from pityriasis versicolor lesions. Therefore, the role of predisposing factors in the conversion of this yeast to mycelium and its subsequent involvement in pityriasis versicolor pathogenicity should be considered

Characterization of the Fungal Microbiota (Mycobiome) in Healthy and Dandruff-Afflicted Human Scalps

The human scalp harbors a vast community of microbial mutualists, the composition of which is difficult to elucidate as many of the microorganisms are not culturable using current culture techniques. Dandruff, a common scalp disorder, is known as a causative factor of a mild seborrheic dermatitis as well as pityriasis versicolor, seborrheic dermatitis, and atopic dermatitis. Lipophilic yeast Malassezia is widely accepted to play a role in dandruff, but relatively few comprehensive studies have been reported. In order to investigate fungal biota and genetic resources of dandruff, we amplified the 26S rRNA gene from samples of healthy scalps and dandruff-afflicted scalps. The sequences were analyzed by a high throughput method using a GS-FLX 454 pyrosequencer. Of the 74,811 total sequence reads, Basidiomycota (Filobasidium spp.) was the most common phylum associated with dandruff. In contrast, Ascomycota (Acremonium spp.) was common in the healthy scalps. Our results elucidate the distribution of fungal communities associated with dandruff and provide new avenues for the potential prevention and treatment of dandruff

Aspectos clínicos de pacientes com pitiríase versicolor atendidos em um centro de referência em dermatologia tropical na cidade de Manaus (AM), Brasil Clinical aspects of patients with pityriasis versicolor seen at a referral center for tropical dermatology in Manaus, Amazonas, Brazil

FUNDAMENTOS: A pitiríase versicolor (tinha versicolor) é uma micose superficial crônica, causada por leveduras do gênero Malassezia spp. comensais das camadas queratinizadas da pele e que, sob determinadas condições ainda não esclarecidas, se torna patogênica, determinando as manifestações clínicas da doença. É uma dermatose recidivante e, mesmo após tratamento, pode deixar hipopigmentação persistente, causando problemas sociais aos indivíduos acometidos. OBJETIVO: Descrever as características clínicas e epidemiológicas de pacientes com diagnóstico de tinha versicolor atendidos em uma unidade de referência em Dermatologia (Fundação Alfredo da Matta). MÉTODOS: Estudo de série de casos em que foram detalhadas as manifestações cutâneas e as características epidemiológicas de pacientes atendidos na Fundação Alfredo da Matta com diagnóstico de tinha versicolor. RESULTADOS: Cento e dezesseis pacientes foram incluídos no estudo no período de janeiro a agosto de 2008. A maioria dos indivíduos é do sexo masculino, de cor parda, da faixa etária jovem e formada por estudantes, que apresentavam fatores predisponentes ao surgimento das manchas. Também a maioria apresentava lesões extensas e história passada da doença. CONCLUSÃO: O estudo mostrou alta proporção de indivíduos com quadros extensos e de longa duração da doença.<br>BACKGROUND: Pityriasis versicolor (tinea versicolor) is a chronic superficial mycosis caused by yeasts of the Malassezia spp. genus commensal of the keratinized layers of the skin. Under conditions not yet understood, it becomes pathogenic determining the clinical manifestations of the disease. It is a recurrent skin condition and persistent hypopigmentation may remain after treatment, causing social problems to those affected. OBJECTIVE: To describe the clinical and epidemiological features of patients diagnosed with tinea versicolor treated at a referral center for dermatology (Alfredo da Matta Foundation). METHODS: Case-studies in which cutaneous manifestations and epidemiological characteristics of patients diagnosed with tinea versicolor treated at Alfredo da Matta Foundation were detailed. RESULTS: One hundred and sixteen patients were included in the study from January to August 2008. Most subjects were male, of mixed ethnicity and young age. Most were students who were predisposed to the development of macules. The majority had extensive injuries and past history of the disease. CONCLUSION: The results revealed a high proportion of individuals with extensive clinical manifestations and duration of the disease