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8.2-CRYPTOCOCCOSIS Flashcards

1
Q

What are the two etiologic agents of Cryptococcosis?

A

Cryptococcus neoformans and Cryptococcus gattii

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2
Q

What type of fungi are Cryptococcus species?

A

Basidiomycetous yeasts

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3
Q

What is a key structural feature of Cryptococcus species?

A

Large polysaccharide capsules

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4
Q

Where is Cryptococcus neoformans found in nature?

A

Dry pigeon feces
Trees
Soil
Other environmental sites

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5
Q

Where is Cryptococcus gattii typically found?

A

Trees in tropical areas

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6
Q

What is the mode of transmission (MOT) for Cryptococcus?

A

Inhalation of desiccated yeast cells or basidiospores

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7
Q

Why is Cryptococcus sometimes considered dimorphic?

A

Because it can show different morphological forms, similar to Candida

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8
Q

In what type of individuals does Cryptococcus neoformans occur?

A

Immunocompetent persons
More commonly in immunosuppressed patients (opportunistic pathogen)

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9
Q

How does Cryptococcus gattii differ from C. neoformans in terms of host preference?

A

Rarer
Affects apparently normal hosts
Less globally prevalent

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10
Q

What is the primary mode of infection for Cryptococcus?

A

Inhalation of yeast cells

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11
Q

What type of infection does Cryptococcus initially cause in the lungs?

A

Primary pulmonary infection

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12
Q

What are the symptoms of a primary pulmonary Cryptococcus infection?

A

Often asymptomatic
May mimic influenza-like respiratory infection
Self-limiting (resolves spontaneously)

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13
Q

In which organ does Cryptococcus primarily disseminate in immunocompromised patients?

A

Central nervous system (CNS) → Cryptococcal meningoencephalitis

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14
Q

What are other common sites of dissemination for Cryptococcus?

A

Skin, adrenals, bone, eye, prostate gland

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15
Q

What type of inflammatory reaction is typically seen in Cryptococcosis?

A

Minimal inflammation
Granulomatous reaction

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16
Q

What is the colonial appearance of Cryptococcus species?

A

Whitish mucoid colonies (appear in 2–3 days)

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17
Q

What is the microscopic appearance of Cryptococcus yeast cells?

A

Spherical budding yeast cells (5–10 μm)
Surrounded by a thick nonstaining capsule

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18
Q

What enzymes do all Cryptococcus species possess?

A

Urease

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19
Q

What are the two key characteristics of C. neoformans and C. gattii?

A

Grow at 37°C
Produce laccase

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20
Q

What bacterial species do Cryptococcus colonies resemble?

A

Klebsiella (both have mucoid, capsule-forming colonies)

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21
Q

What unique microscopic feature is seen in Cryptococcus?

A

Halo appearance around yeast cells (due to thick capsule)

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22
Q

What fungal species does Cryptococcus yeast cell morphology resemble?

A

Blastomyces (broad-based budding)
Paracoccidioides (Mickey Mouse cap or Mariner’s wheel)

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23
Q

What are the five serotypes of Cryptococcus?

A

A, B, C, D, AD

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24
Q

Which serotypes does Cryptococcus neoformans have?

A

A, D, AD

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25
What is the anamorph of Cryptococcus neoformans?
Filobasidiella neoformans var. neoformans
26
Which serotypes does Cryptococcus gattii have?
B, C
27
What is the anamorph of Cryptococcus gattii?
Filobasidiella neoformans var. bacillispora
28
What classification group do Cryptococcus species belong to?
Perfect fungi
29
What is the structure of Cryptococcus capsular polysaccharides?
α-1,3-linked polymannose backbone β-linked branches of xylose and glucuronic acid
30
Where can solubilized Cryptococcus capsular polysaccharides be detected?
Spinal fluid, serum, or urine
31
What diagnostic tests detect Cryptococcus capsular antigens?
Enzyme immunoassay (EIA) Latex agglutination test
32
Can patient antibodies to the Cryptococcus capsule be used for diagnosis?
No (not diagnostic)
33
What is the mode of transmission for Cryptococcus?
Inhalation of desiccated yeast cells or basidiospores
34
What is the initial site of infection for Cryptococcus
Pulmonary alveoli
35
What are the primary sources of infection for Cryptococcus?
C. neoformans: Avian feces (pigeon droppings), trees C. gattii: Trees
36
What happens after inhalation of Cryptococcus?
Phagocytosed by alveolar macrophages Infection may resolve or become latent May disseminate to multiple sites, especially the CNS → Meningoencephalitis
37
cryptococcal meningitis CSF findings
↑ Pressure, ↑ Protein, Elevated cell count, Glucose normal or low
37
What are the symptoms of pulmonary cryptococcosis in immunocompetent patients?
Often asymptomatic
37
What are the radiologic findings in pulmonary cryptococcosis?
Coin lesions (localized or diffuse infection)
37
What are the main clinical findings of cryptococcal meningitis?
Resembles brain tumor, abscess, CNS disease, or other fungal/mycobacterial meningitis Skin, lungs, or other organs may also have lesions
38
Symptoms cryptococcal meningitis
Headache, neck stiffness, disorientation
38
What culture temperature is best for Cryptococcus?
Room temperature (RT) or 37°C
38
What is the fatality rate of untreated cryptococcal meningitis?
100% (ultimately fatal if untreated)
38
How do skin lesions occur in cryptococcosis?
Hematogenous dissemination from the respiratory tract (RT) in immunocompromised patients
38
What do cryptococcal skin lesions look like?
Papular lesions Ulcerative (can be single or multiple)
38
How significant is Cryptococcus in fungal-related deaths?
Causes 25% of all fungal-related deaths
38
How does pulmonary cryptococcosis present in immunocompromised patients?
Extensive infection, often co-infection with Pneumocystis jiroveci Cytomegalovirus (CMV)
38
Is Cryptococcus transmitted from person to person?
No
38
What are the main serologic tests for Cryptococcus?
Latex slide agglutination test Enzyme immunoassay (EIA)
38
What test detects phenoloxidase (laccase) activity in Cryptococcus?
Guizotia abyssinica agar test → Brown pigment production
38
What specimens are used for cryptococcal diagnosis?
CSF (for CNS involvement) Tissue biopsy Exudates (for skin lesions) Sputum (for pulmonary infection) Blood (for disseminated infection) Cutaneous scrapings (for skin lesions) Urine
38
What stain is used for direct microscopic examination of Cryptococcus?
India ink preparation (delineates the capsule)
38
How do Cryptococcus bone/joint infections occur?
Dissemination from RT infection
38
What are the hallmark features of Cryptococcus bone infections?
Osteolytic lesions Abscess formation Joint space involvement
39
What is the sensitivity of Cryptococcal antigen testing in meningitis cases?
90% positive in cryptococcal meningitis
39
What media should be avoided in Cryptococcus culture?
Media containing cycloheximide
39
How many deaths per year does Cryptococcus cause in Africa?
600,000 deaths per year
39
What are the two main antigen-antibody detection methods?
Detect patient antibodies (using reagent antigen) Detect Cryptococcus antigens (using reagent antibodies)
39
What enzymes are used to identify Cryptococcus in culture?
Urease production Phenoloxidase (laccase) → Produces melanin
39
How do antigen titers change with treatment?
Titers drop with successful therapy
39
What is the leading cause of meningitis in sub-Saharan Africa?
Cryptococcus neoformans
39
What is the standard treatment for cryptococcal meningitis?
Combination therapy of Amphotericin B + Flucytosine
39
What is the treatment for non-HIV/AIDS cryptococcosis?
Amphotericin B (± Flucytosine) → Curative in most cases
39
What is immune reconstitution inflammatory syndrome (IRIS) in cryptococcosis?
Seen in HAART-treated AIDS patients Causes paradoxical relapse May unmask undiagnosed cryptococcosis
39
What environmental reservoir is associated with C. gattii?
Trees, soil, and water
39
What is the primary reservoir of Cryptococcus?
Bird droppings (especially pigeon droppings)
39
How does HAART therapy affect cryptococcosis in HIV/AIDS patients?
Lower incidence due to lower HIV viral load Better prognosis
39
What region is called the "Meningitis Belt of the World"?
Africa
39
Which group of patients is highly susceptible to Cryptococcus?
Patients on corticosteroids
39
Which serotype of C. neoformans causes most global cases?
Serotype A
39
Where has C. gattii emerged in recent years?
Pacific Northwest (Vancouver Island → British Columbia, Washington, Oregon, California, Idaho)

MYCOVIRO (22 decks)

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