Malassezia species: Pathology, isolation and identification media

The Malassezia genus comprises yeasts whose natural habitat is the skin of humans and warm-blooded animals. They are responsible for various pathological aspects. The study of these yeasts has been postponed for many years due to its nutritional requirements and its morphological variability. Molecular biology methods led to a taxonomic revision of this genus and to a new interest for its clinical importance. The Dixon medium supports not only the growth of these yeasts but also gives morphological and physiological pathognomonic characters. In comparison with modified Dixon, the medium of Leeming and Notman is more adapted to the conservation of the species. A system of identification, based on assimilation tests of non-ionic detergents such as tweens and cremophor EL on Sabouraud dextrose agar, was very useful. It makes possible a definition of characteristic patterns for the various species of Malassezia. Recently a kit of identification of nine species was developed. This method is based on the production of precipitation on a modified Chromagar Candida. (C) 2009 Elsevier Masson SAS. All rights reserved.