Clinical and epidemiological features of the genus Malassezia in Iran

BACKGROUND AND OBJECTIVES The genus Malassezia contains an expanding list of lipophilic yeasts involve in the etiology of various superficial fungal infections. Pityriasis versicolor (PV) is the most prevalent Malassezia-related infection distributed worldwide. In the present study, clinical and epidemiological features of the genus Malassezia are discussed with special focus on PV in Iran. MATERIALS AND METHODS During June 2012 to April 2013, among 713 confirmed cases of fungal infections, 68 (9.5%) were diagnosed as PV by positive direct microscopy results in 20% potassium hydroxide (KOH) preparation of skin scrapings. All the specimens were cultured on modified Dixon agar and incubated at 32°C for 10 days. Identification of the isolated yeasts was carried out based on macro- and microscopic morphology, catalase test, utilization of Tweens, polyethoxylated castor oil (EL slant), and hydrolysis of esculin and utilization of Tween-60 (TE slant). RESULTS Out of 68 skin scrapings, 55 (80.9%) yielded yeast colonies on mDixon's agar which were finally identified as M. globosa (36.36%), M. pachydermatis (29.08%), M. furfur (23.65%), M. slooffiae (7.28%) and M. obtusa (3.64%). CONCLUSION Results of the present study further indicate clinico-epidemiological importance of the genus Malassezia with growing importance of M. pachydermatis as a major species involve in the etiology of pityriasis versicolor. These findings are of major concern in management of Malassezia-related diseases.