Malassezia pachydermatis

Colonies on Sabouraud dextrose agar are cream to yellowish, and typically smooth to slightly wrinkled with lobate margins [1270]. This species is the only non-lipid dependant isolate in the genus Malassezia. Adequate growth occurs without addition of olive oil but some strains may exhibit enhanced growth when olive oil is added.

Cornmeal preparations reveal ellipsoidal cells measuring 2.0-2.5 x 4.0-5.0 µm. Wet preparations reveal yeast cells with daughter cells being produced from a very broad base and leaving behind distinct collarettes.

This isolate is primarily associated with animals, most notably with canines [926], but has also been implicated in a hospital outbreak in a neonatal unit [1294]. It is differentiated from other Malassezia spp. by its ability to grow on routine laboratory media without the addition of an oleic acid source.

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

PubMed

GenBank

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.

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

1294. Larocco, M., A. Dorenbaum, A. Robinson, and L. K. Pickering. 1988. Recovery of Malassezia pachydermatis from eight infants in a neonatal intensive care nursery: clinical and laboratory features. Pediatric Infectious Disease Journal. 7:398-401.