Cutaneous and Subcutaneous Mycoses PART 3 Flashcards
SUBCUTANEOUS MYCOSES:
a. Mycetoma
b. Chromoblastomycosis
c. Phaeohyphomycosis
d. Sporotrichosis
chronic granulomatous infection that usually involves the lower extremities
Mycetoma
Subcutaneous Mycoses
infection is characterized by swelling, purplish discoloration, tumor-like deformities of the subcutaneous tissue, and multiple sinus tracts that drain purulent material containing
yellow, white, red, or black granules called grains
Mycetoma
Subcutaneous Mycoses
- The infection gradually progresses to involve the bone, muscle, or other contiguous tissue and ultimately requires amputation in
most progressive case
Mycetoma
Subcutaneous Mycoses
Mycetomas usually are seen among people living in
tropical
and subtropical regions
The organisms associated with mycetoma are saprophytic and commonly found in soil, standing water, and sewage. Humans acquire infections through traumatic implantation of
the organism into the skin and subcutaneous tissues
Mycetoma
Subcutaneous Mycoses
Mycetoma Subcutaneous Mycoses
- Two types:
1 Actinomycotic (bacterial) mycetomas
2 Eumycotic (fungal) mycetomas
caused by the aerobic actinomycetes, including
Nocardia, Actinomadura, and Streptomyces spp.
Actinomycotic (bacterial) mycetomas
- Caused by a heterogeneous group of fungi that have septate hyphae
- Subcategorized as white grain mycetomas or black grain mycetomas
Eumycotic (fungal) mycetomas
is the most common fungal agent
associated with mycetoma
Madurella mycetomatis
Direct examination of clinical specimens from patients with a eumycotic mycetoma or phaeohyphomycosis demonstrates
yellowish brown, septate to moniliform
hyphae (string of beads), with or without budding yeast cells present
White Grain Mycetoma
Scedosporium spp
Acremonium spp
grow rapidly (5 to 10 days) on common laboratory media. Initial growth begins as a white, fluffy colony that changes in several weeks to a brownish gray (the so-called mousy gray) colony; the reverse of the colony progresses from tan to dark brown.
Scedosporium spp
cause mycetomas, such as Acremonium falciforme, grow slowly and produce gray colonies.
Acremonium spp
Black Grain Mycetoma
Madurella spp.
E. jeanselmei
Curvularia spp
T. grisea
appear yeastlike and darkly pigmented (olive to black) but in time develop a velvety appearance with the production of aerial
hyphae.
E. jeanselmei
vary from white (during the early phases of growth) to olive-brown; a brown
diffusible pigment is characteristic of this fungus.
Madurella spp
produce a fluffy or downy, olive-gray
to black colony, and growth is rapid.
Curvularia spp.
forms slow-growing, velvety colonies that
appear smooth or radially furrowed and dark gray or olive-brown to black. The reverse side of the colonies appears black. The hyphae are septate and nonsporulating.
T. grisea
-a chronic fungal infection acquired through traumatic inoculation of an organism, primarily into the skin and subcutaneous tissue
- characterized by the development of a papule at the site of the traumatic insult that slowly enlarges to form warty or tumorlike lesions characterized as resembling cauliflower
capable of spreading through the lymphatic system
Chromoblastomycosis
Subcutaneous Mycoses
The lesions usually are confined to the feet and legs but may involve the head, face, neck, and other body surfaces
Chromoblastomycosis
Subcutaneous Mycoses
Histologic examination of the lesion reveals characteristic sclerotic bodies which are copper-colored, septate cells that appear to be dividing by binary fission and resemble copper
pennies.
Chromoblastomycosis
Subcutaneous Mycoses
Infections cause hyperplasia of the epidermal layer of the skin, which may be mistaken for squamous cell carcinoma
Chromoblastomycosis
Subcutaneous Mycoses
Chromoblastomycosis is widely distributed, but most cases occur in the ___ of the world
tropical and subtropical areas
The fungi most often associated with
chromoblastomycosis include
Cladophialophora carrionii,
Fonsecaea monophora and pedrosoi Phialophora verrucosa
Scrapings from crusted lesions added to 10%
KOH show muriform cells (aggregation of dark
brown cells that resemble stones in a
stonewall) or sclerotic bodies, which are
rounded, brown, 4 to 10 μm in diameter, and have fission planes. They resemble copper
pennies
Laboratory Diagnosis
Chromoblastomycosis
Laboratory Diagnosis
Chromoblastomycosis - includes species that produce long chains of budding, often fusiform, conidia (blastoconidia) that have
a dark septal scar.
Cladosporium
Laboratory Diagnosis
Chromoblastomycosis includes species that produce short, flask-shaped to tubular phialides, each with a well-developed collarette
- Produce colonies that are wooly and olive-brown to brownish gray; some strains may appear to have concentric zones of color
Phialophora
ncludes organisms that exhibit a mixed type of
sporulation produces a distinct Fonsecaea-type conidiophore, may also produce a Rhinocladiella-type sporulation
Fonsecaea
Cladophialophora type of sporulation with long chains of elliptical conidia (2 to 3
μm × 4 to 5 μm) borne from erect, tall, branching conidiophores
Cladophialophora (C. carrionii)
produces phialides, each with a distinct cup- or
flask-shaped collarette
P. verrucosa
produces phialides with a flattened
collarette. Conidia are produced endogenously and occur in clusters at the tip of the phialide
P. richardsiae
Conidial heads with sympodial arrangement
of conidia are seen, with primary
conidia giving rise to secondary conidia
Fonsecaea spp
a general term used to describe any infection caused by a dematiaceous organism
Phaeohyphomycosis
Subcutaneous Mycoses
Includes molds; brownish, yeastlike cells; pseudohyphae; and hyphae
Phaeohyphomycosis
Subcutaneous Mycoses
These infections may be subcutaneous, localized, or systemic .Include phaeohyphomycotic cysts, progressive soft tissue infection, brain abscess, sinusitis, endocarditis, mycotic keratitis,
pulmonary infection, and systemic infection
Phaeohyphomycosis
Subcutaneous Mycoses
Symptoms often include headache, neurologic manifestations, and seizure
Phaeohyphomycosis
Subcutaneous Mycoses
Phaeohyphomycosis Subcutaneous Mycoses
- The most common fungal isolates associated with neurologic manifestations include
C. bantiana,
Rhinocladiella mackenziei,
Verruconis gallopava
Exophiala dermatitidis.
are also commonly associated with phaeophyomycosis
Alternaria, Exserohilum, Bipolaris, E. jeanselmei, Exophiala spinifera, and Curvularia spp.
Laboratory Diagnosis
Phaeohyphomycosis colonies are rapidly growing, fluffy, and gray to gray-brown or gray-green.
Alternaria spp
produce rapidly growing colonies that
resemble those of Alternaria spp
Curvularia spp
produce colonies that are gray-green to dark
brown and slightly powdery, as do Exserohilum spp.
Bipolaris spp.
grow slowly (7 to 21 days) and initially produce shiny, black, yeastlike colonies.
E. jeanselmei and E. dermatitidis
● Bacterial: Nocardia, Actinomadura, and
Streptomyces spp.
● White grain mycetoma: S. apiospermum
complex and Acremonium and Fusarium spp.
● Black grain mycetoma: Madurella
spp., E. jeanselmei, and Curvularia spp.
Mycetoma
Cladophialophora, Phialophora,
and Fonsecaea spp.
Chromoblastomycosis
E. jeanselmei; E.dermatitidis; and
Curvularia, Bipolaris, Alternaria, and Exserohilum sp
Phaeohyphomycosis
is a subcutaneous infection, but lymph and
pulmonary infections can occur
Sporotrichosis
Also known as rose gardener’s disease, as infections can come from rose thorns and contact with sphagnum moss
Sporotrichosis
have a worldwide distribution, and their natural habitat is living or dead vegetation.
S. schenckii,
Sporothrix brasiliensis,
Sporothrix globosa,
Sporothrix luriei
-It is a dimorphic fungus
- When grown on media with blood at 35°C, these fungi grow as small yeasts
Sporothrix schenckii
When grown on SDA or PDA at room temperature, they are in the _____ phase characterized by delicate hyphae and
microconidia
mold phase / Sporothrix schenckii
