Transcript dematacious_fungi

M. Refai
Dematiaceous Fungi
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The term "dematiaceous" refers to the characteristic
dark appearance of this group of fungi as it grows on
agar.
Colonies are dark gray, brown, or black and,
importantly, have a black reverse when the bottom
of the agar plate is examined.
Hyphae are dark yellow or brown when unstained or
poorly stained
This distinguishes the dematiaceous fungi from
fungi with black conidia but an otherwise pale
mycelium, such as A. niger.
A. flavus
A. fumigatus
A. niger
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Dematiaceous Fungi with Muriform Macroconidia
 Alternaria
 Stemphylium
 Ulocladium
 Epicoccum
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Note muriform septation in the macroconidia indicated by the
arrow
Conidia form chains or occur singly and are divided by transverse
and longitudinal septations; conidia usually have a club-shaped
configuration
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Dematiaceous Fungi with Transversely
Septated
Macroconidia
 Curvularia
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Drechslera
.characteristic
boomerang shaped macroconidia
Dematiaceous Fungi with Microconidia
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Cladosporium
Phialophora verrucosa
Fonsecaea pedrosoi
Wangiella dermatitidis
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Dematiaceous Fungi that Defy the Above
Grouping
 Phaeoannellomyces werneckii
 Chaetomium species
.Note
the 2 celled yeast forms
Perithecia with radially extending irregular brown filamentous setae
Alternaria tenuis
Nees, 1817
Alternaria chartarum,
Alternaria dianthicola,
Alternaria geophilia,
Alternaria infectoria,
Alternaria
stemphyloides, and
Alternaria teunissima
Alternaria species
•Colonial
Morphology:
Grows rapidly as
downy to wooly,
pale grey to brown
on the surface and
brown to black on
reverse
Stemphylium botryosum
Wallroth, 1833
The genus
Stemphylium contains
several species,
the most common one
is Stemphylium
sarcinaeforme
Ulocladium botrytis
Preuss, 1851
The genus
Ulocladium
comprises
9 species
Curvularia species
Drechslera species
Bipolaris
species
Pithomyces chartarum
Cladosporium
Trejos, 1954
The genus comprises over 30 sp.
Cladosporium elatum,
Cladosporium herbarum,
Cladosporium
sphaerospermum, and
Cladosporium cladosporioides.
Many species have been
classified in different other
genera such as Exophiala,
Fonseceae etc.
Phialophora verrucosa
Thaxter, 1915
The Phialophora species
commonly involved
P. verrucosa,
P. hoffmanni,
P. parasitica,
P. repens and
P. richardsiae.
Phialophora parasitica
Phialophora
parasitica
•Colonial
Morphology:
Moderately slow
growing, matures
in 7 days. Initially
cream colored and
velvety, becoming
olive grey to black
with age. Reverse
black.
Phialophora richardsiae
Conant, 1937
Cladophialora carioni
Cladophialophora
bantiana
(Xylohypha bantiana)
Lactophenol Aniline Blue
•Magnification: x250
Magnification: x400
Rhinocladiella atrovirens
Fonsecaea.
Powell, 1952
comprises species
classified previously
in the genera
Phialophora,
Hormodendrum
Cladosporium
F. compacta
F. pedrosoi
Fonsecaea pedrosoi
Fonsecaea compacta
Exophiala jeanselmei
•Specimen: leg mass
•Black yeast
Exophiala castellanii,
Exophiala moniliae,
Exophila pisciphila,
Exophiala salmonis,
Exophiala spinifera.
Exophiala spinifera
•Specimen: Bronchial
Washing
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Wangiella dermatitidis
•Specimen: Bronchial
Washing
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Hortae
(Phaeoannellomyces)
Phaeoannellomyces
werneckii
(Cladosprium werneckii)
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Phaeococcomyces
Aureobasidium pullulans
Petriella setifera
•Colonial
Morphology: White,
dark grey, brownish,
becoming granular
due to perithecium
production
•Stain:
Lactophenol
Aniline Blue x400
•Structure:
Conidiophores
arising from
undifferentiated
hyphae, producing
single celled
hyaline, ovoid
conidia on the
slimy heads.
Calcofluor
White
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Magnificat
ion: x400
Dactylaria gallopova
Chaetomium SP
black perithecium
Phoma Sp.
Stachybotrys-atra
Chromoblastomycosis
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The ethiologic agents belong to the Fonsecaea,
Phialophora, Rhinocladiella and
Cladosporium genera .]5 ,4[ The causal agents
are normally found as saprophytes in the soil,
wood and vegetation .]3[ They are more
frequent in the tropics but have a worldwide
distribution .]7[ The vast majority of cases are
attributed to Fonsecaea pedrosoi
1.Chromomycosis
• characterized by the formation of
warty cutaneous nodules that develop
very slowly, ultimately forming
prominent papillomatous vegetations
which may or may not ulcerate.
• Usually the lesions are confined to the
feet and legs but may occur on the
hands, face, ear, neck, chest or
shoulders.
• The most common causes are
Fonsecaea pedrosoi, F. compactum
Hand
chromoblastomycosis
The dermis contains multiple
black nodules with necrotic foci
Mycetoma
Madura foot
Maduromycosis
•is a chronic infection characterized by
the development of tumifactions and
sinuses.
•The infection most often occurs in the
feet but may appear on the hands or
buttocks.
•The organism occasionally invades
the body producing lesions in the brain,
the meninges and other internal
organs, including the bones.
•The disease occurs most frequently in
tropical and subtropical zones.
•The numerous fungi that have been
isolated from cases of maduromycosis
belong to several genera.
•The dematiaceous fungi causing this
disease fall in the genera Madurella,
Phialophora , Curvularia ,
Pyrenochaeta and Leptosphaeria.
•These fungi produce black granules in
the lesions.
•Other non-dematiaceous fungi that
produce white to yellow granules
include Cephalosporium, Petriellidium
etc
Mycetoma
Excision of fistule-forming
inflammatory nodule at the
ankle of a Japanese man
demarcated
suppurative
granuloma containing
black grains
3. Phaeohyphomycosis:
•This term refers to infections, other than
chromomycosis and maduromycosis,
characterized by the presence of darkly
pigmented, septate hyphae in tissues. Both
cutaneous and systemic
•The clinical forms vary from solitary
encapsulated cysts in the subcutaneous
tissue to brain abscesses.
•The phaeomycotic cyst usually develops on
the extremities and may enlarge to several
centimeters
The most common causes of phaeohyphomycotic
diseases are:
a. Phaeomycotic cyst: Exophiala jeanselmei, Wangiella
dermatitidis, E. spinifera, Phialophora hoffmannii, P.
parasitica, P. repens, P. richardsiae, Bipolaris spicifera.
b. Subcutaneous phaeohyphomycosis: B. spicifera,
Alternaria alternata, P. richardsiae, E. jeanselmei,
Hermonema dermatitidis.
c. Systemic phaeohyphomycosis: A. alternata, B.
spicifera, Aureobasidium pullulans, Dactylaria
constricta.
d. Brain abscesses: Cladophialophora bantiana,
Curvularia lunata.
Brain Biopsy
• Stain: Gram Stain
Structure: Long hyphae appearing
pseudohyphae, observe septum. No indication
of pigmentation.
Other diseases and problems caused by
dematiacious fungi
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Allergy
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Mycotoxicosis
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Ocular infections in cats and a dog
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Color change and biodeterioration of
antique marbles, walls, ceiling etc.
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Food spoilage
- Black spots in frozen meat
- Vegetable and fruit rot
Stachybotryotoxicosis
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Stachybotryotoxicosis is a disease in animals
caused
by
satratoxins
produced
by
Stachybotrys alternans.
The disease is manifested by 4 forms: a dermal
form, generalized form, nervous form and
abortion. In man it causes conjunctivitis,
cough, rhinitis and skin inflammation.
Myrotheciotoxicosis
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Myrotheciotoxicosis is a disease of sheep,
sometimes also cattle
It is caused by the toxins verrucarin A and
roridin A, produced by Myrothecium species.
The disease is characterized by tympany and
high mortality
Pithomycotoxicosis
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Pithomycotoxicosis is a disease of sheep and cattle
associated with the consumption of plant stubs
contaminated with sporidesmin produced by
Pithomyces chartarum.
It is characterized by diarrhoea and reduction of milk
yield, photosensitization of the skin resulting in
inflammation, oedema and serous exudation.