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House Microbiology > Fungal Meningitis- Cryptococcus > Flashcards

Fungal Meningitis- Cryptococcus Flashcards

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1
Q

Cryptococcus

Ubiquitous (unencapsulated or encapsulated?) (yeasts or molds?) belonging to the division __________.

_______________ are inhaled from environment

The fungus (can or cannot?) spread from person to person

A

encapsulated; yeasts

Basidiomycota

Fungal spores

Cannot

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2
Q

Cryptococcus

Over _____ species of Cryptococcus are known, however, Cryptococcus _______ and C._____ are the two main species implicated in nearly all cases of human cryptococcosis.

A

70

neoformans; gattii

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3
Q

Cryptococcus

C. neoformans has 2 distinct varieties:

C. neoformans var. _________
C. neoformans var. ________

Other species of less clinical significance includes:
C. ________ , C._______, C. _______, etc.

A

neoformans

grubii

laurentii; adeliensis; albidus

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4
Q

Cryptococcus

Yeast: ______ or ______ shaped

• _______ in diameter

•Surrounded by ___________________

•20-30mm thick

A

round or oval

4-6mm

polysaccharide capsules

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5
Q

Cryptococcus

“_______” cells

~90-100 mm

___________

______vely stains with India Ink and nigrosin

Stains with ______ and ___________

A

Titan

Melanised

Negati

PAS and mucicarmine

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6
Q

C. neoformans

Frequently isolated from _______ contaminated with ______ or other ______ and NOT in _________________.

A

soil; pigeon

bird droppings

fresh wet droppings

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7
Q

C. neoformans

The precise link between C. neoformans and birds to date remains ________.

A

unclear

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8
Q

Birds get infected with C. Neoformans

T/F

A

F

They do not

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9
Q

C. gattii

Isolated from _______ in the _____ group of _________ trees, cedar, oak and other native trees.

A

decaying wood

red gum

eucalyptus

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10
Q

C. gattii has been isolated from bird droppings.

T/F

A

F

C. gattii has not been isolated from bird droppings.

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11
Q

C. gattii affects _________________ patients

C. neoformans affects _____ patients (98% _________ patients, Rarely ___________)

A

Immunocompetent

HIV; Immunocompromised; immunocompetent

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12
Q

C. neoformans var neoformans affects _______________ patients

A

Immunocompromised; rarely immunocompetent

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13
Q

Cryptococcosis refer to infections caused by any species of the genus __________.

Cryptococcus spp. are capable of causing diseases in ______________________________________ individuals.

A

Cryptococcus

both immunocompetent and immunocompromised

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14
Q

_________ is the most common clinical manifestation of cryptococcosis.

A

Cryptococcal meningitis

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15
Q

Disseminated cryptococcal disease is largely associated with ______/_____

A

HIV/AIDS.

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16
Q

__________ —————- disease is largely associated with HIV/AIDS.

A

Disseminated cryptococcal

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17
Q

Virulence factors of cryptococcus

Polysaccharide capsule formation
Comprised of _________________ (GXM) and _____________ (GalXM)

A

glucuronoxylomannan

galactoxylomannan

18
Q

Virulence factors
Polysaccharide capsule formation

Key roles
Anti-_________
Antibody _____________
Inhibition of ______________
Deregulation of _______________
Interference with ___________________
L-selectin & tumor necrosis factor loss

A

phagocytic

unresponsiveness

leucocyte migration

cytokine secretion

antigen presentation

19
Q

Virulence factors of cryptococcus

Major virulence
__________ formation
________ pigment production
Ability to grow well at ___0C
____________ ————

A

Polysaccharide capsule

Melanin; 37

Phenotypic switching

20
Q

Virulence factors of cryptococcus

Other virulence
Secreted _________________
______ production
Enzymes associated with ________ against _____________

A

phospholipase B

Urease

protection

oxidative stresses

21
Q

Who are at risk?
C. neoformans

_____(80-90%)
Idiopathic CD4 ______
________ malignancies and disorders

Long-term ________ and /or immunosuppressive therapy
_______ and _______ transplant recipients
___________

A

HIV; lymphopenia

Lymphoproliferative

corticosteroid

Solid organ & bone marrow

Sarcoidosis

22
Q

Who are at risk?
C. neoformans

Treatment with _______ antibodies
____________ diseases
Hyper-Ig___ or Hyper-Ig__ syndromes

Decompensated _______disease

_____ failure and /or peritoneal _____

Adult-onset immunodeficiency

A

monoclonal

Rheumatological

M; E

chronic liver

Renal; dialysis

23
Q

Virulence factors of cryptococcus neoformans

Melanin pigment production
Catalyzed by the enzyme ________________

A

Phenol oxidase

24
Q

Virulence factors
Melanin pigment production

Key Roles
Anti________
Cell wall _______ and _______
Interference with ____-cell response

Reduction of susceptibility to antifungal agents
__________ of antibody mediated phagocytosis
Protection from extreme ________

A

oxidant
support and integrity
T

Abrogation; temperature

25
Q

Virulence factors: Phenotypic switching

Occurs during ______ infection
Common in serotype ____ and ____ strains of C. neoformans

Associated with differential ______ and _______ changes in virulence

“_______” cell formation

A

chronic

A and D

gene expression and capsule

Titan

26
Q

Cryptococcus are _______ encapsulated _____.

C.______ and C.____ are the two main species implicated in clinical
disease.

A

ubiquitous; yeasts

neoformans; gatti

27
Q

C. neoformans var. grubii (serotype ___) is the most common cause of ______ disease in HIV/AIDs patients.

A

A

disseminated

28
Q

C.________ var. ——— (serotype ___) is the most common cause of disseminated disease in HIV/AIDs patients.

A

neoformans

grubii

A

29
Q

Who are at risk: C. gattii

Predominantly immuno__________ individuals

A

competent

30
Q

Who are at risk: C. gattii

Other risk factors1
•HIV (___-___%)
•Current ______
•Age (>___ years)
•History of ________

A

10-20

Smoker

50; invasive cancers

31
Q

Cryptococcus & HIV

Cryptococcus is the ____________ leading opportunistic infection in patients with HIV/AIDS.

Patients with CD4 <____ are the most at risk.

A

2nd or 3rd

100

32
Q

Cryptococcus & HIV

Cryptococcus is responsible for up to ____% (13-44%) of the HIV/AIDS deaths.

6% of the global HIV/AIDS population with under _____ CD4 cells are CrAg positive, with substantial geographical variability

A

100

33
Q

Cryptococcal disease

Cryptococcal infection is associated with a range of illness.

In some people, the fungus causes a lung infection similar to ———-, or it can cause ______________.

The incubation period is _______, but it is thought that the infection can ____________________________.

A

tuberculosis; no symptoms at all.

not known

remain dormant in the body for many years

34
Q

Cryptococcal disease

In immunosuppressed people , particularly HIV-infected people with CD4 counts under 100, the infection can _____ and ____________________.

Cryptococcal _______, most common presentation.

A

reactivate

spread throughout the body

Meningitis

35
Q

Clinical Presentations
Cryptococcal Meningitis
Typical :

_______ onset of fever and headache

________ and/or meningeal signs in only 25%

A

Subacute

Photophobia

36
Q

Clinical Presentations
Cryptococcal Meningitis

Less typical
•_______
•__________
• Progressive _______
• __________ impairment
• FUO

A

Seizures

Confusion

dementia

Visual or hearing

37
Q

Investigations of CNS Cryptococcal infection
Csf sample
______ ml volume needed
____eased yield if multiple CSF samples

A

3 - 5

incr

38
Q

Investigations of CNS Cryptococcal infection

Csf examination

Measure opening pressure (OP):
• 50% of HIV+ patients have OP >_____ cmH20
• (Raised Or Lowered?) lymphocytes
•(Raised or Lowered?) protein
•(Low or High?) glucose
Indian Ink & fungal culture & CRAG

A

25

Raised

Raised

Low

39
Q

Summary of Diagnostic Options

Culture
____________ colonies within 48hours
_______ cultures often (+) in immunosuppressed patients
2/3rds with _________

• Tissue
_______ or ______ stain
________ for CSF

•Cryptococcal antigen
Serum and CSF are 99% sensitive in _____ patients
Serum is (more or less?) sensitive in normal hosts

A

White mucoid
Blood
Meningitis

Silver or mucicarmine
India ink

AIDS
Less

40
Q

Cryptococcal meningitis is a common cause of death among HIV/AIDS patients

T/F

A

T

41
Q

In some areas of the world, cryptococcal meningitis is estimated to cause more deaths than tuberculosis (TB)

T/F

A

T

House Microbiology (93 decks)

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