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Description and Habitats Verticillium
mould
is a widely distributed filamentous fungus that inhabits decaying vegetation
and soil. Some Verticillium species may be pathogenic to arthropods,
plants, and other fungi. It is commonly considered as a contaminant.
Verticillium may very rarely cause human disease.
Species
Based on the
informative website,
www.doctorfungus.com , the genus Verticillium has four
known species; Verticillium affinae, Verticillium albo-atrum,
Verticillium fusisporum, and Verticillium luteoalbum.
Health Effects
Members of this genus are often isolated from the environment. It has
been reported as a rare agent of mycotic keratitis.
Mycosis:
Hyalohyphomycosis
A mycotic infection of man or animals caused by a number of hyaline (non-dematiaceous)
hyphomycetes where the tissue morphology of the causative organism is
mycelial. This separates it from phaeohyphomycosis where the causative
agents are brown-pigmented fungi. Hyalohyphomycosis is a general term used
to group together infections caused by unusual hyaline fungal pathogens
that are not agents of otherwise-named infections; such as Aspergillosis.
Etiological agents include species of Penicillium, Paecilomyces,
Acremonium, Beauveria, Fusarium, and Scopulariopsis.
The clinical manifestations of hyalohyphomycosis are many ranging from
harmless saprophytic colonization to acute invasive disease. Ideally,
individual disease states involving invasive fungal infection by a hyaline
hyphomycete should be designated by specific description of the pathology
and the causative fungal genus or species (where known); for example
"pathology A" caused by "fungus X".
Predisposing factors include prolonged neutropenia, especially in
leukemia patients or in bone marrow transplant recipients, corticosteroid
therapy, cytotoxic chemotherapy and to a lesser extent patients with AIDS.
The typical patient is granulocytopenic and receiving broad-spectrum
antibiotics for unexplained fever.
Macroscopic
Features
Colonies
of Verticillium grow moderately rapidly or rapidly. At 25°C and on
potato dextrose agar, the colonies are velvety to wooly. From
the front, the color is white initially and becomes yellowish, red,
pinkish-brown, or green. From the reverse, it is white or brown (rust
color).
Microscopic
Features
Septate
hyaline hyphae, conidiophores, phialides, and conidia are observed.
Conidiophores are hyaline, simple or branched. The branching of the
conidiophores occurs in whorls (= verticillate; resembling spokes in a
wheel from a central axis) at several levels. Conidiophores bear the
phialides. Phialides are very long and are also arranged in verticils
(whorls) around the conidiophore. Verticils may be disrupted in slide
culture. The apices of the phialides are pointed. Conidia (2-13µm in
length) are hyaline or brightly colored, one-celled, and oval to pyriform
in shape. They are solitary or form clusters in sticky heads at the tips
of the phialides.
Laboratory
Precautions
No
special precautions other than general laboratory precautions are
required.
Susceptibility
Very
few data are available. Per these data on very limited number of isolates,
amphotericin
B, ketoconazole,
itraconazole,
and voriconazole
appear active in vitro against Verticillium mould. |
