Detection of Malassezia Species Isolated From Patients With Pityriasis Versicolor and Seborrheic Dermatitis Using Nested-PCR

Background: The species of the genus Malassezia are lipophilic and dimorphic yeasts that are regarded as part of the normal flora of the skin of humans and warm-blooded animals. These organisms are the cause of superficial mycosis in humans and other animals, and are common in pityriasis versicolor and seborrheic dermatitis. Objectives: The purpose of this study was to determine the frequency of common Malassezia species in patients affected by pityriasis versicolor and seborrheic dermatitis using of the nested PCR method, in the city of Ahvaz. Patients and Methods: In the present study, 85 samples from patients with pityriasis versicolor and seborrheic dermatitis were analyzed by the nested-PCR method. During the first stage, the internal transcribed spacer (ITS) region from the ribosomal DNA was reproduced using primers ITS4-R and ITS1F-N. During the second stage, the product of the first step was used as DNA and using three special primer pairs, including Mf-F, 5.8SR and M.gl-F, 5.8SR and M.rt-F and M.rt-R, the inner part of the first phase was detected. Results: The most common isolate was Malassezia furfur (51.3%) followed by M. globosa (35.2%) and M. restricta (13.5%). Amongst the 30 patients with seborrheic dermatitis, in 15 cases (65.2%) M. restricta, in six cases (26.1%) M. globosa and in two cases (8.7%) M. furfur was detected and in seven patients no isolate was detected. Conclusions: The nested-PCR is a rapid and repeatable method for identification of important Malassezia species and this method is recommended for use on more patients. In addition the most common agents of pityriasis versicolor and seborrheic dermatitis were M. furfur and M. restricta, respectively.