Malassezia furfur

Colonies on Sabouraud dextrose agar overlaid with olive oil and incubated at 30°C are cream to yellowish, and typically smooth to slightly wrinkled [1270]. Colony size is difficult to assess due to growth in oil. Colonies grown on mDixon agar are mat to dull, smooth to umbonate, with a soft or friable texture [927].

Cornmeal preparations do not work well with this species due to the oleic acid (olive oil) requirements. Wet preparations from plates overlaid with olive oil reveal yeast cells with daughter cells being produced from collarettes also known as bud scars. Cell shape and size is variable ranging from oval to cylindrical, to spherical. Dimensions range from 1.5-5.0 x 2.5-8.0 µm.

This isolate is an obligate saprobe or opportunistic pathogen of humans and is rarely recovered from animals [926]. It is differentiated from M. sympodialis and M. slooffiae by it ability to grow on glucose/peptone agar with 10% Tween 20. Disease states include pityriasis versicolor, seborrheic dermatitis, dandruff, atopic dermatitis, and psoriasis [943].

Susceptibility testing according to NCCLS/CLSI Document M27-A2 is not possible due to the oleic acid requirement of this species.

PubMed

GenBank

Growth on medium overlaid with olive oil

References

926. Gueho, E., and S. A. Meyer. 1989. A reevaluation of the genus Malassezia by means of genome comparison. Antonie Van Leeuwenhoek. 55:245-51.

927. Gueho, E., G. Midgley, and J. Guillot. 1996. The genus Malassezia with description of four new species. Antonie van Leeuwenhoek. 69:337-355.

943. Gupta, A. K., R. Batra, R. Bluhm, T. Boekhout, and T. L. Dawson, Jr. 2004. Skin diseases associated with Malassezia species. J Am Acad Dermatol. 51:785-98.

1270. Kurtzman, C. P., and J. W. Fell (ed.). 2000. The Yeasts. A Taxonomic Study. Elsevier Scientific B.V., Amsterdam, The Netherlands.