Genus Malassezia: Taxonomic classification and clinical significance in animals and man

The historical development of the taxonomic classification of Malassezia ye asts until today yielded the description of seven different species based u pon molecularbiological, morphological and biochemical parameters (M. furfu r, M. pachydermatis, M. sympodialis, M. globosa, M. obtusa, M. restricta, M . slooffiae). Tests like Cremophor EL assimilation, esculin degradation, ca talase test, pigment production and determination of polidocanol sensitivit y appear to be suitable procedures for routine identification of the differ ent species. Their colonization of clinically healthy humans (in particular M. sympodialis, M. globosa, M. obtusa) and animals (M. pachydermatis) skin renders interpretation difficulties, when isolating Malassezia spp. from c linical specimens. Out of the seven species, in man the clinical significan ce of M. furfur for pityriasis versicolor and systemic infections appears t o be accepted largely. In dogs and cats M. pachydermatis has been regarded as cause of otitis externa and seborrhoeic dermatitis. But, due to geno- an d phenotypic variabilities described for M. pachydermatis field isolates fu rther investigations concerning the taxonomic uniformity of the species are nessessary.