Malassezia species isolated from lesional and nonlesional skin in patients with pityriasis versicolor

Abstract

Objectives This study aimed to identify Malassezia species found in pityriasis versicolor (PV) patients as well as to establish whether there is any association between the various species of Malassezia isolated from lesional and from nonlesional skin of those patients. Background PV is a common, benign, superficial cutaneous fungal infection caused by Malassezia species usually characterized by hypopigmented or hyperpigmented macules and patches on the chest and back. These lesions are scaly and their color varies from red, pale, yellow brown to dark brown. Patients and methods A total of 100 patients with PV were included in the study. The samples were obtained by scraping the skin surface, both from lesional and from nonlesional skin, and then incubated on Dixon's agar. The yeast isolated were identified using conventional biochemical tests and Tween assimilation. Results Skin lesions were 100% KOH positive for Malassezia species and 10% KOH positive in healthy skin. Growth from skin lesion was obtained on Dixon's agar in 83 patients (83%). The most common species was Malassezia furfur as it was detected in 47 samples (47%), followed by Malassezia globosa (23%) and Malassezia sympodialis (13%). From healthy skin of patients, growth of Malassezia was obtained from 19 specimens, M. furfur was detected in 13%, and M. globosa was detected in only three patients (3%) and M. sympodialis in three patients (3%). Conclusion M. furfur in its mycelial phase was the predominant species involved in the etiology of PV and M. globosa was the second most common species. The most frequently isolated species from clinically healthy skin was M. furfur and was recovered from healthy skin only in yeast form. We found no difference in the distribution of Malassezia species between lesional and nonlesional skin. Furthermore, no species predominance was observed whether with hyperpigmented or hypopigmented lesions as M. fufur was the most common species in both lesions in PV patients.