Subcutaneous Mycoses Flashcards
(52 cards)
How do subcutaneous mycoses typically enter the body?
Through traumatic implantation of foreign objects into the skin
Where are the causative agents of subcutaneous mycoses commonly found?
Soil or decaying vegetation
What are two other names for chromoblastomycosis?
“Verrucous dermatitis” and “chromomycosis”
How is chromoblastomycosis acquired?
By traumatic inoculation of the organism into the skin
What is a characteristic clinical feature of chromoblastomycosis lesions?
Warty, tumor-like lesions that resemble cauliflower
How does chromoblastomycosis spread within the body?
Through the lymphatic system
What structures are seen in tissue that resemble “copper pennies”?
Sclerotic bodies
What is another term for “copper-colored, septate cells” that divide by binary fission?
Muriform cells
Name three fungal species that cause chromoblastomycosis
Cladophialophora carrionii, Fonsecaea pedrosoi, Phialophora verrucosa
What type of specimen is collected for laboratory diagnosis?
Scrapings from crusted lesions
What laboratory test can be used to detect muriform cells in a sample?
10% potassium hydroxide (KOH) test
What molecular method can be used to confirm the diagnosis?
MALDI-TOF MS (Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry)
What is the microscopic appearance of Phialophora verrucosa?
Phaeoid (darkly pigmented), flask-shaped phialides with a well-developed collarette
What is the colony appearance of fungi that cause chromoblastomycosis?
Darkly pigmented colonies (gray to olive black), velvety or suede-like texture
What is a characteristic feature of Cladophialophora carrionii sporulation?
Sporulation occurs in long chains of elliptical conidia
What type of fungi cause Phaeohyphomycosis?
Darkly pigmented (phaeoid) fungi
What distinguishes Phaeohyphomycosis from other fungal infections?
The presence of melanin in the fungal cell walls
What are three clinical manifestations of Phaeohyphomycosis?
Phaeohyphomycotic cysts, brain abscess, pulmonary infection, sinusitis, systemic infection
Name at least three fungal genera that cause Phaeohyphomycosis.
Alternaria spp., Bipolaris spp., Cladophialophora spp., Curvularia spp., Exophiala spp.
What laboratory stains are used to detect fungal melanization?
Fontana-Masson, 10% Silver Nitrate, Ammonium hydroxide
How does Fontana-Masson stain help identify Phaeohyphomycosis?
It detects melanization in fungal cell walls
What microscopic structure is characteristic of Bipolaris spp.?
Drumstick” appearance of conidia arranged in chains
What is the germ tube test result for Cladophialophora spp. at 25°C after 24 hours?
Germ tubes form at both ends at 25°C after 24 hours.
What feature of Curvularia spp. makes conidia easily dislodged?
Shield cells in wet mounts, which easily dislodge from conidia chains
