Biology Report: Characteristics and Diseases of Malassezia Species

This report provides a detailed overview of Malassezia species, including their microscopic appearance, colony morphology, and normal habitats. It describes the characteristics of several species, such as M. furfur, M. dermatis, M. restricta, and M. japonica, highlighting their distinct features under a microscope and their growth patterns on Sabouraud's agar. The report also discusses the diseases caused by these species, including pityriasis, dandruff, tinea circinata, and seborrheic dermatitis, and explains the confirmatory tests used for species identification, such as diffusion methods and catalase reactions. Furthermore, the report references several scientific sources to support the information presented, offering a comprehensive understanding of these important fungal organisms and the conditions they cause.

Running head: MALASSEZIA SPECIES 1
Malassezia Species
Student’s Name
Institutional Affiliation

MALASSEZIA SPECIES 2
Microscopic appearance (Microscopic cell morphology) of Malassezia species.
M. furfur cells are spherical and consist of a different bottleneck at one end. It is typically
found in single cell individuals although unlike other species of Malassezia it forms filaments
when it becomes its pathogenic form. M. dermatis appear as oval or round budding yeast-like
cells of 3 to 8 μm in diameter staining dark blue. The cells shape is ovoid, ellipsoidal or globose
and its budding is monopolar on a moderately broad base (Garrison & Arnold, 2018). On the
other hand, the shape of the cells of M. restricta is ovoid or globose, and budding is monopolar
on a relatively narrow base. The cells of M. japonica are short ovoid to cylindrical of about 33
μm with budding which is monopolar on a broad base.
Colony morphology on Sabouraud’s agar.
When malassezia species colonies are sowed in Sabouraud’s agar, M. dermatis due to its
lipophilic attributes form globular shaped yeast with its cells round shaped which appear
elongated maintaining a narrow base. M. furfur is lipophilic although able to produce small
colonies without supplementation of lipids in which its colonies appear to be cream to yellow-
brown and they appear smooth and soft and friable, often becoming brittle and wrinkled as they
age (Celis, Wösten & de Cock, 2017). The colonies of M. restricta appear small, flat or raised
colonies 1 to 2 mm in diameter on average, pale yellowish-brown, dull, smooth with a lobate
margins and M. japonica form flat, slightly wrinkled single colonies around 2 to 3 mm in
diameter, pale yellowish cream, dull and butyrous with a straight or folded margin.
Normal habitat.
Malassezia furfur needs an environment high in fats and oils to flourish since it is
lipophilic yeast hence lives on the epithelial cells of humans where it consumes the natural oils

MALASSEZIA SPECIES 3
and fats excreted. It can be found mostly on the arms, chest, and shoulders and develops best
about 35 ˚C. Malassezia dermatitis is caused by Malassezia pachydermatis bacteria which
generally live in small numbers in the ears on animal skin and the mucosal surfaces such as
vaginal, oral and anal of healthy dogs and cats (Shokri, 2016). However, M. restricta along with
M. japonica reside in the scalp and trunk of humans.
Diseases they cause.
M. furfur, a lipophilic, dimorphic and yeast-like fungus occurring in the skin of humans
as an opportunistic pathogen causes infections like pityriasis, dandruff, tinea circinata along with
seborrheic dermatitis a disease which causes skin lesions (Grice & Dawson, 2017). Malassezia
dermatitis causes a thickening of the skin called lichenification making the skin resemble an
elephant's hide. Malassezia restricta causes prolonged fever along with splenic lesions, and it is
also related to seborrhoeic dermatitis or dandruff. Moreover, M. japonica has also been
associated with dandruff.
Confirmatory tests for identification of the species.
Through the method of diffusion the ability to use individual tweens that is, 20, 40, 60
and 80 are assessed, catalase reaction determined along with describing the yeast cell
morphology. M. dermitis, M. restricta, and M. japonica have stable morphological
characteristics except for M. furfur (Misra & Jain, 2018). M. dermitis is non-lipid dependent and
hence could be developed on conventional media. M. dermitis, M. japonica, and M. furfur
contain catalase except for M. restricta.

MALASSEZIA SPECIES 4
References
Celis, A. M., Wösten, H. A., & de Cock, H. (2017). Physiological characterization of lipid
assimilation in M. pachydermatis. Unraveling lipid metabolism in lipid-dependent
pathogenic Malassezia yeasts, 41.
Garrison, R. G., & Arnold, W. N. (2018). Atlas of cell morphology. In Yeast Cell Envelopes
Biochemistry Biophysics and Ultrastructure (pp. 13-32). CRC Press.
Grice, E. A., & Dawson, T. L. (2017). Host–microbe interactions: Malassezia and human
skin. Current opinion in microbiology, 40, 81-87.
Misra, V., & Jain, A. K. (2018). Isolation and identification of Malassezia species from patients
of pityriasis versicolor and its comparison with normal subjects. indian journal of applied
research, 7(9).
Shokri, H. (2016). Occurrence and distribution of Malassezia species on skin and external ear
canal of horses. Mycoses, 59(1), 28-33.