[Examination of the causative agent of pityriasis versicolor].

Pityriasis versicolor (PV) is a superficial infection of the stratum corneum caused by Malassezia. Eleven species have been recognized within this genus, namely M. globosa, M. restricta, M. sympodiasis, M. furfur, M. obtusa, M. slooffiae, M. pachydermatis, M. dermatis, M. japonica, M. yamatoensis, M. nana. To examine the distribution of the microorganism in the skin of patients with PV, we detected Malassezia species without M. pachydermatis and M. nana using a non-culture-based method that consisted of nested PCR with specific primers. The most frequently isolated species were M. globosa and M. restricta (both 93.9%). M. globosa was detected in scales in which only the mycelial form (yeast cells, < 10/sample) were observed microscopically; M. restricta was not found. We suggest that M. globosa is the causative agent of PV.