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Flashcards in Mycology II Deck (42):
1

What is Cryptococcosis associated with?

Associated with pigeon droppings and soil

2

What are some predisposing factors to cryptococcocsis?

- AIDS

- Most common predisposing factor in non-AIDS patients is receipt of large doses of adrenal corticosteroids.

- Sarcoidosis and lymphoma also predispose to infection

3

What can cryptococcosis hematogenously spread to once infected?

CNS

4

What is required for clearing the cryptococcosis infection?

Activated T cells

5

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

6

What will chest x-ray of someone with cryptococcosis show?

CXR will show one or more well- localized infiltrates

7

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.

8

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

9

Are C. neoformans encapsulated?

Yes

10

What is a good lab technique for diagnosis of cryptococcosis?

Cryptococcal Antigen Latex Agglutination

11

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

12

What are some of the stains that can be used for Cryptococcus?

- Gram Stain
- GMS Stain
- India Ink
- Mucicarmine Stain

13

What are main infectious dimorphic fungi?

– Histoplasma capsulatum
– Blastomyces dermatitidis
– Coccidioides immitis
– Sporothrix schenckii

14

What are the 2 forms of dimorphic fungi and when do they form?

• Yeast like cells at 35 C
• Mold form at 25 C

15

Where is Histoplasma capsulatum found and what regions of the US?

• Found in soil, bird and bat droppings
• Concentrated in Ohio / Mississippi River Valleys

16

What city is the epicenter of Histoplasma?

Indianapolis

17

What are the clinical manifestations of H. capsulatum infection?

• Asymptomatic (antibody present)

• Pulmonary
– Infiltrates, mediastinal lymphadenopathy – May progress to cavitating lesion
– Fever, night sweat, weight loss (like TB)

• Disseminated
– Febrile illness
– Spread to CNS, skin, adrenals
– Enlarged liver and spleen

18

What regions of the world is Cryptococcus found in?

World wide

19

What is seen in Histoplasmosis?

Pneumonia - granuloma in the lung with macrophages that are filled with Histoplasma

20

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

21

What are fingerlike projections from macroconidia seen on microscopy indicative of?

Histoplasmosis

22

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

23

What is the epicenter of Blastomyces?

Chicago

24

What are the clinical manifestations of Blastomycosis?

• Pulmonary
– Fever, chest pain, cough with sputum
– Hilar lymphadenopathy, nodular lesion
• Skin lesions (necrosis and fibrosis)
• Lytic bone lesions
• Disseminated disease

25

What are broad-based budding and lollipop conidia indicative of?

Blastomyces dermatiditis

26

What stains are needed to visualize Blastomyces?

GMS or PAS stains

27

What are the endemic areas of Coccidioidomycosis?

US southwest

28

Is Coccidioidomycosis transmitted person to person?

NO

29

What is the pathogenesis of coccidiomycosis?

• Inhalation of arthroconidia bypasses upper airway into alveoli
• Monocytes ingest arthroconidia
• Arthroconidia converts to spherule

30

What size are coccidiodes spherules compared to RBCs?

Much larger

31

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

32

What are the other names for Coccidiomycosis?

• “San Joaquin Valley Fever”
• “Desert Rheumatism”

33

What are some clinical manifestations of Coccidides immitis infection?

- Erythema nodosum
- Fever, cough, chest pain, malaise

34

What are the diagnostic tests for coccidiomycosis?

• Microscopic exam to detect spherules
• Culture
– Demonstrate alternating arthroconidia
– DNA probe of colony
• Skin test turns positive 1-4 weeks
• Serology useful unless anergic

35

What do C. immitis spherules typically contain?

Endospores

36

What are alternating barrel shaped conidia indicative of?

C. immitis

37

What can Sporothrix schenckii cause and what is this disease also known as?

"Rose gardener's disease" - Sporotrichosis

38

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

39

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

40

How is sporotrichosis diagnosed?

Culture and microscopy

41

Chromoblastomycosis Clinical Manifestations?

Papules􏰂 - verrucous cauliflower-like lesions on lower extremities

42

What are some agents that cause chromoblastomycosis?

DO NOT MEMORIZE

– Phialophora verrucosa
– Fonsecaea pedrosoi
– Fonsecaea compacta
– Cladophialophora carrionii
– Rhinocladiella aquaspera

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