Flashcards in Mycology II Deck (42):
What is Cryptococcosis associated with?
Associated with pigeon droppings and soil
What are some predisposing factors to cryptococcocsis?
- Most common predisposing factor in non-AIDS patients is receipt of large doses of adrenal corticosteroids.
- Sarcoidosis and lymphoma also predispose to infection
What can cryptococcosis hematogenously spread to once infected?
What is required for clearing the cryptococcosis infection?
Activated T cells
What are the clinical manifestations of cryptococcosis?
• Most patients will have meningoencephalitis at presentation
• Present with headache, nausea, gait abnormalities, dementia, irritability. Cranial nerve abnormalities and hydrocephalus due to basilar meningitis occur. Fever and nuchal rigidity may be mild
• Skin lesion
What will chest x-ray of someone with cryptococcosis show?
CXR will show one or more well- localized infiltrates
What do colonies of Cryptococcus grow like?
Colonies are fast growing, soft, glistening to dull, smooth, usually mucoid, and cream to slightly pink or yellowish brown in color. The growth rate is somewhat slower than Candida and usually takes 48 to 72 h.
What about its growth separates C. neoformans from the other Cryptococcus?
Ability to grow at 37°C is one of the features that differentiates Cryptococcus neoformans from other Cryptococcus spp. - this is how it causes disease in the human body
Are C. neoformans encapsulated?
What is a good lab technique for diagnosis of cryptococcosis?
Cryptococcal Antigen Latex Agglutination
Cryptococcal Antigen Latex Agglutination
– Highly sensitive and specific
– Can detect antigen in CSF and serum
– Has diagnostic and prognostic value
– Method of choice for diagnosing patients with cryptococcal meningitis
What are some of the stains that can be used for Cryptococcus?
- Gram Stain
- GMS Stain
- India Ink
- Mucicarmine Stain
What are main infectious dimorphic fungi?
– Histoplasma capsulatum
– Blastomyces dermatitidis
– Coccidioides immitis
– Sporothrix schenckii
What are the 2 forms of dimorphic fungi and when do they form?
• Yeast like cells at 35 C
• Mold form at 25 C
Where is Histoplasma capsulatum found and what regions of the US?
• Found in soil, bird and bat droppings
• Concentrated in Ohio / Mississippi River Valleys
What city is the epicenter of Histoplasma?
What are the clinical manifestations of H. capsulatum infection?
• Asymptomatic (antibody present)
– Infiltrates, mediastinal lymphadenopathy – May progress to cavitating lesion
– Fever, night sweat, weight loss (like TB)
– Febrile illness
– Spread to CNS, skin, adrenals
– Enlarged liver and spleen
What regions of the world is Cryptococcus found in?
What is seen in Histoplasmosis?
Pneumonia - granuloma in the lung with macrophages that are filled with Histoplasma
What are the diagnostic tests for Histoplasmosis?
• Culture of bone marrow, biopsy, BAL
• Skin test with histoplasmin
– Positive test shows past exposure
– Not to diagnose acute infection
• Urine Antigen Test
What are fingerlike projections from macroconidia seen on microscopy indicative of?
What is Blastomyces dermatitidis associated with and in what regions of the US is it found?
Associated with soil and wood and it is found in the central US
What is the epicenter of Blastomyces?
What are the clinical manifestations of Blastomycosis?
– Fever, chest pain, cough with sputum
– Hilar lymphadenopathy, nodular lesion
• Skin lesions (necrosis and fibrosis)
• Lytic bone lesions
• Disseminated disease
What are broad-based budding and lollipop conidia indicative of?
What stains are needed to visualize Blastomyces?
GMS or PAS stains
What are the endemic areas of Coccidioidomycosis?
Is Coccidioidomycosis transmitted person to person?
What is the pathogenesis of coccidiomycosis?
• Inhalation of arthroconidia bypasses upper airway into alveoli
• Monocytes ingest arthroconidia
• Arthroconidia converts to spherule
What size are coccidiodes spherules compared to RBCs?
Where can coccidiomycosis disseminate to from the lungs?
Dissemination to bone, skin, squamous and mucosal tissues, meninges, joints and other sites can follow 1o pulmonary infection
What are the other names for Coccidiomycosis?
• “San Joaquin Valley Fever”
• “Desert Rheumatism”
What are some clinical manifestations of Coccidides immitis infection?
- Erythema nodosum
- Fever, cough, chest pain, malaise
What are the diagnostic tests for coccidiomycosis?
• Microscopic exam to detect spherules
– Demonstrate alternating arthroconidia
– DNA probe of colony
• Skin test turns positive 1-4 weeks
• Serology useful unless anergic
What do C. immitis spherules typically contain?
What are alternating barrel shaped conidia indicative of?
What can Sporothrix schenckii cause and what is this disease also known as?
"Rose gardener's disease" - Sporotrichosis
What are the clinical manifestations of sporotrichosis and what are the sites of dissemination?
• Papular skin lesion enlarges and ulcerates
• Firm nodules form along lymphatics
• Multiple ulcers
• Disseminates to bones, lungs, eyes, CNS
What is the pathogenesis of sporotrichosis?
• Inhalation of conidia or traumatic inoculation of skin
• Organism multiplies at local site
• Pyogenic and granulomatous response
• Infection spreads via the lymphatics
- Pulmonary sporotrichosis is rare
How is sporotrichosis diagnosed?
Culture and microscopy
Chromoblastomycosis Clinical Manifestations?
Papules - verrucous cauliflower-like lesions on lower extremities