Medical Mycology (Habal) Flashcards
What fungus causes tinea corporis/cruris/pedis/capitis/unguium/manus? Clinical presentation: invasion of keratinized structures with possible secondary bacterial infections and mild inflammatory response in infected areas.
Dermatophytes
What fungus causes soft, pale nodules on hair in groin and axilla?
White Piedra - Tienea blanca, Trichosporon beigelii
What fungus causes and small, dark nodules on hair shaft)?
Black Piedra - Piedra hortae
What fungus causes Pityriasis versicolor - hypopigmented spots on chest, back, arms, shoulders, face, or neck? May also occur in lipid-dependent yeast in young adults with oily skin.
Malassezia furfur
What fungus causes Sporotrichoses (Rose Gardener’s Disease) - local pustules and ulcers with nodules at site of infection and along draining lymphatics? May also spread secondarily to articular surfaces, bone, and muscle.
Sporothrix schenckii
What may happen to the immunocompromised if they are infected by Sporothrix schenckii?
Fungus (Sporothrix schenckii) may become disseminated.
What fungus causes the “Summer Flu” of the Midwest?
Histoplasma capsulatum
What fungus may affect the spleen, liver, and bone marrow; is often asymptomatic, may resemble TB pneumonia as progressive lung disease, may cause ocular histoplasmosis, and disseminates in immunocompromised patients?
Histoplasma capsulatum
What fungus causes “Chicago Disease”; fever, night sweats & weight loss; pulmonary stage which may be followed by chronic granulomatous stage (lung & skin granuloma may ulcerate), and may affect the spine, pelvis, cranial bones, and ribs?
Blastomyces dermatitidis
What fungus causes “San Joaquin Valley Feve”; fever, productive cough, chest pain, extreme fatigue (usually self-limited), erythema multiforme & granulomas called Desert Bumps, is often associated with anorexia, and has symptoms that appear 7-28 days after exposure?
Coccidioides immitis
What fungus causes disease of the lungs and skin that rarely becomes systemic?
Paracoccidiodes brasiliensis
What fungus causes lung injury and meningioencephalitis (fever, loss of vision, stiff neck, mental status change, possibly hydrocephalus)?
Cryptococcus neoformans
What fungus causes infection ranging from mild (diaper rash) to fatal (systemic)? Name this infection.
Candida species - Candidiasis
What fungus causes vulvovaginitis, cutaneous candidiasis, oral thrush, esophageal candidiasis, and disseminated candidiasis?
Candida albicans
What is an AIDS-defining illness caused by a fungus? (Name the fungus as well.)
Esophageal candidiasis - Candida albicans
What fungus causes mycotoxicosis - ingestion of contaminated foods, possible precursor to liver cancer?
Aspergillus fumigatus
What fungus causes allergy/sequelae to presence of conidia or transient growth of organism in body orifices; colonization without extension in preformed cavities and debilitated tissues, and invasive, inflammatory granulomatous disease of lungs and other organs?
Aspergillus fumigatus
What fungus causes mold growth on organic material, such as bread?
Zygomycosis
What fungus causes large clots that lead to infarctions & pneumonia; has no boundaries, causes headache & orbital cellulites, leads to cerebral nerve palsy, hemorrhage, coma, and death if not treated?
Zygomycosis - Mucor or Rhizopus
What fungus causes bilateral infiltrate in lungs, fever, non-productive cough, breathing difficulty, respiratory failure, cyanosis, death by asphyxia, and rarely, extrapulmonary disease? 100% fatal if untreated.
Pneumocystis jiroveci
What is the most common fungal cause of pneumonia?
Pneumocystis jiroveci
What fungus can cause disease at sites distant to local infection and severe GE disease similar to cryptosporidiosis in AIDS?
Microsporidiosis
Which fungi cause superficial infections?
Piedras, Dermatophytes, Malassezia furfur
Which fungus causes subcutaneous infections?
Sporothrix schenckii
Which fungi cause systemic fungal infections?
Histoplasma capsulatum, Blastomyces dermatitidis, Coccidiodes immitis, Paracoccidiodes brasiliensis
Which fungi are opportunistic mycoses?
Candida albicans, Cryptococcus neoformans, Aspergillus fumigatus, Mucor rhizopus, Pneumocystis jiroveci
What do fungi release and why?
Release enzymes to degrade the environment for nutritive purposes.
Fungi exist in what type of form? What does this mean?
They are thermally dimorphic - can exist in different forms, yeast or mold, depending on temperature.
What are the 4 components of fungal structure?
Polysaccharide capsule, cell wall, cell membrane, cytoplasm
What is the only encapsulated fungus we’re discussing?
Cryptococcus neoformans
Describe the cell membrane of fungi.
Similar to eukaryotic cell membrane - bilayered, made up of phospholipids and sterols, the latter of which is very important as some organisms need nutrients in order to synthesize them.
Describe yeast.
Unicellular, asexual budding reproduction, sexual reproduction, may contain capsule (identified via India ink), aerobic, grows at wide range of temperatures (optimum at room temp)
Describe mold.
Aerobic, filamentous, multicellular, spore/conidia reproduction, filaments known as hyphae (collection = mycelium, collection of these = mycelia, collection of these = mold
What is a defining characteristic of hyphae? What is the name for this, and is it characteristic of all mold?
Fenestrated septate - separations in hyphae that allow for transfers of material between compartments. Not all hyphae have these; they’re known as unseptate hyphae.
What is pseudohyphae?
Lack of cytoplasmic connections between cells - see constriction in middle.
Which fungus is pseudohyphae?
Candida
What is a germ tube?
Hyphae sticking out of a spore. This is a virulence factor that is very invasive when systemic.
What does fungal pathogenesis ultimately depend upon? What else?
Transmission is #1, but also depends on immune response.
How are most fungal infections transmitted?
Via the environment.
Which fungi are transmitted via human-human contact?
Dermatophytes
What are the 3 main ways to ID fungus in a lab?
Sabouraud’s agar, blood agar, microscopy