Wangiella dermatitidis is a black (melanized)
fungus that is recognized as a paradigm for the
emerging human mycosis known as phaeohyphomycosis and
also as a model for the more than one hundred other
black fungi known to cause human disease.[1,2,3]
Since its first isolation in Japan in 1937 and its
description as a skin pathogen, Wangiella has
been assigned to numerous Fungi Imperfecti genera, is
known to have a world-wide distribution, and has been
isolated from most body sites, including the brain, in
both immunocompromised and immunocompetent patients.
Its elevation to model status for the black fungi is
based on its polymorphism, which can be manipulated
experimentally to produce for detailed study
homogeneous populations each of
characteristic in vivo and in vitro
of all of the other
pathogenic black fungi. In addition, and to date, it
is the only black fungal pathogen of humans for which
numerous molecular tools are available for study of
its biology and the basis of its virulence.
- Matsumoto, T., L. Ajello, T. Matsuda, P. J.
Szaniszlo and T. J. Walsh. Developments in
hyalohyphomycosis and phaeohyphomycosis. J. Med.
Vet. Mycol. Suppl. 32 (1994) 329-349.
- Szaniszlo, P. J. Molecular genetic studies of
the model dematiaceous pathogen Wangiella
dermatitidis. Int. J. Med. Microbiol. 292
- Szaniszlo, P. J. Virulence factors in black
molds with emphasis on melanin, chitin and
Wangiella as a molecularly tractable model, p.
407-428. In: J. Heitman, S. G. Filler, J. E. Edwards
and A. P. Mitchell (ed). Molecular Principles of
Fungal Pathogenesis. (2006). ASM Press, Washington,
What is Wangiella (Exophiala)
dermatitidis (in more detail)?
Wangiella dermatitidis is a pathogen of humans
that causes a disease known as phaeohyphomycosis.
Although typically referred to as a black yeast, this
asexual species is, in fact, a conidiogenous mold that
has been molecularly classified among the
Chaetothyriomycetidae, one of the two subclasses of the
Eurotiomycetes class of the Ascomycota.
Traditionally most associated with dermatotropic forms
of disease, in the manner of most black fungi, it is
being reported with increasing frequency as a systemic
pathogen with a marked neurotropic tendency.
Predisposing factors for the systemic forms include
cystic fibrosis, lymphocytic leukemia, diabetes
mellitus, bronchiectasis, rheumatoid arthritis and
catheterization. Initiation of both the dermatotropic
and systemic disease forms is attributed to the
traumatic implantation of the fungus into tissue,
although in some cases the rout of infection is unknown
and pulmonary entry has not been ruled out.[4,5]
In vivo W. dermatitidis is manifested as a
plethora of darkly pigmented morphotypes, which include
polarized thin-walled and ovoid budding yeast, and septated
and branched or unbranched true, moniliform or pseudohyphae
and nonpolarized and isotropically enlarged thick-walled
forms variously termed sclerotic cells and planate cells,
together with an infrequent sclerotic (muriform) body.
The pigmentation of all the morphotypes is due to the
deposition into the cell walls of W. dermatitidis of
the polymerization product 1,8-dihydroxynaphthalene,
a known virulence factor in this species and
most likely all other of the fungal pathogens of humans
similarly melanized. These characteristics, plus the ability
of investigators to experimentally manipulate switching
among the many morphotypes and to produce them in vitro for
study in homogeneous populations, as well as
the increasing molecular tractability of W. dermatitidis,
suggested that it would be an exceptional candidate for
whole genome sequencing. The data generated are expected to
confirm further that this species warrants its status as a
model for the black pathogenic fungi. Since the alternate
morphotypes of this species are also induced by or have
tolerance for a variety of very stressful conditions, such
as extremely low pH, nitrogen and calcium limitation,
elevated temperatures, and radiation resistance,
it would not be surprising to find that these data also will
be useful to those who are studying the variety of
nonpathogenic black fungi that exist in nature under these
and other extremely stressful conditions.
- Matsumoto, T., L. Ajello, T. Matsuda, P. J. Szaniszlo
and T. J. Walsh. Developments in hyalohyphomycosis and
phaeohyphomycosis. J. Med. Vet. Mycol. Suppl. 32
- Geiser, D. M., C. Gueidan, J. Miadlikowska, F. Lutzoni,
F. Kauff, V. Hofstetter, E. Fraker, C. L. Schoch, L.
Tibell, W. A. Untereiner, and A. Aptroot. 2006.
Eurotiomycetes: Eurotiomycetidae and Chaetothyriomycetidae.
Mycologia 98, 1053-1064.
- Matsumoto, T., Matsuda, T., McGinnis, M.R., Ajello.
L., 1993. Clinical and mycological spectra of Wangiella
dermatitidis infections. Mycoses 36,145-155.
- Lebecque, P., A. Leonard, H. Daniel, R. Gregory, A.
Boreras, T. Leal and F. Symoens. 2010. Exophiala
(Wangiella) dermatitidis and cystic fibrosis -
prevalence and risk factors. Med. Mycol. Suppl. 4854-59.
- Horre, R., and G.S. de Hoog. 1999. Primary cerebral
infections by melanized fungi: a review. p.176-193. In
G. S. de Hoog (ed.). Studies in Mycology 43.
Centraalbureau voor Schimmelcultures, Baarn/Delft, The
- Szaniszlo, P. J. Molecular genetic studies of the
model dematiaceous pathogen Wangiella dermatitidis.
Int. J. Med. Microbiol. 292 (2002) 283-289.
- Wheeler, M. H., D. Abramczyk, L. S. Puckhaber, M.
Naruse, Y. Ebizuka, I. Fujii and P. J. Szaniszlo. A new
biosynthetic step in the melanin pathway of Wangiella
(Exophiala) dermatitidis: evidence for
2-acetyl-1,3,6,8-tetrahydroxynaphthalene as a novel
precursor. Eukaryot. Cell 7 (2008) 1699-1711.
- Feng, B., X. Wang, M. Hauser, S. Kauffmann, S. Jentsch,
G. Haase, J. M. Becker, and P. J. Szaniszlo. Molecular
cloning and characterization of WdPKS1, a gene involved in
melanin biosynthesis and virulence in Wangiella
(Exophiala) dermatitidis. Infect. Immun. 69
- Abramczyk, D., C. Park, and P. J. Szaniszlo.
Cytolocalization of the class V chitin synthase in the
yeast, hyphal and sclerotic morphotypes of Wangiella
(Exophiala) dermatitidis. Fungal Gen. Biol. 46 (2009)
- Szaniszlo, P. J. Virulence factors in black molds with
emphasis on melanin, chitin and Wangiella as a
molecularly tractable model, p. 407-428. In: J. Heitman,
S. G. Filler, J. E. Edwards and A. P. Mitchell (ed).
Molecular Principles of Fungal Pathogenesis. (2006). ASM
Press, Washington, D.C.
Phaeohyphomycosis, in the broad sense, sometimes
is said to include several
additional human syndromes,
which include black-grained mycetoma,
chromoblastomycosis, tinea nigra, black piedra, keratitis, and onychomycosis.