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.
Tarazooie
Bita
B
Department of Medical Mycology & Parasitology, School of Public Health and Institute of Public Health Research, Tehran University of Medical Sciences, Tehran, Iran. btarazooie@razi.tums.ac.ir
Kordbacheh
Parivash
P
Zaini
Farideh
F
Zomorodian
Kamiar
K
Saadat
Farshid
F
Zeraati
Hojjat
H
Hallaji
Zahra
Z
Rezaie
Sassan
S
D000328:Adult; D017677:Age Distribution; D016022:Case-Control Studies; D015897:Comorbidity; D003920:Diabetes Mellitus / Q000453:epidemiology; D005260:Female; D006801:Humans; D006945:Hyperhidrosis / Q000453:epidemiology; D006967:Hypersensitivity / Q000453:epidemiology; D007492:Iran / Q000453:epidemiology; D008290:Malassezia / Q000145:classification*; D008297:Male; D015995:Prevalence; D012016:Reference Values; D017678:Sex Distribution; D012867:Skin / Q000382:microbiology*; D013045:Species Specificity; D014010:Tinea Versicolor / Q000453:epidemiology* / Q000382:microbiology*