Physiological and Molecular Characterization of Atypical Isolates of Malassezia furfur

The species constituting the genusMalassezia are considered to be emergent opportunistic yeasts of great importance. Characterized as lipophilic yeasts, they are found in normal human skin flora and sometimes are associated with different dermatological pathologies. We have isolated sevenMalassezia species strains that have a different Tween assimilation pattern from the one typically used to differentiateM. furfur ,M. sympodialis , andM. slooffiae from otherMalassezia species. In order to characterize these isolates ofMalassezia spp., we studied their physiological features and conducted morphological and molecular characterization by PCR-restriction fragment length polymorphism and sequencing of the 26S and 5.8S ribosomal DNA-internal transcribed spacer 2 regions in three strains from healthy individuals, four clinical strains, and eight reference strains. The sequence analysis of the ribosomal region was based on the Blastn algorithm and revealed that the sequences of our isolates were homologous toM. furfur sequences. To support these findings, we carried out phylogenetic analyses to establish the relationship of the isolates toM. furfur and other reported species. All of our results confirm that all seven strains areM. furfur ; the atypical assimilation of Tween 80 was found to be a new physiological pattern characteristic of some strains isolated in Colombia.