Meningtitis (Neisseria menigitidis) Flashcards

Neisseria menigitidis

1
Q

Key Characteristics of Neisseria meningitidis.

A

Gram Negative
Diplococcus
Twitching Motility
Aerobic
Fastidious
Oxidase Positive
Asymptomatic coloniser of the nasopharynx (pathobiont)

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2
Q

How is Neisseria meningitidis transmitted?

A

Droplets

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3
Q

How many different serogroups of Neisseria meningitidis are there?

A

12

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4
Q

What are the 5 most common servo-groups of Neisseria meningitidis?

A

A
B
C
W135
Y

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5
Q

Where does Neisseria meningitidis reside?

A

Upper Respiratory Mucosa

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6
Q

What does the first stage of infection involve?

A

The bacteria passing through to the bloodstream by endocytosis and then migrating to the blood-brain barrier

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7
Q

What happens at the blood brain barrier?

A

The bacteria passes through and causes meningitis

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8
Q

How does Neisseria meningitidis survive in the bloodstream?

A

Its capsule provides protection against antibodies and phagocytosis

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9
Q

What do most isolates of Neisseria meningitidis produce to overcome the host’s secretory IgA antibodies?

A

IgA proteases

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10
Q

Pathogenesis of Neisseria meningitidis

A
  1. Attaches to brain endothelial cells using IV pili, allowing microcolony formation.
  2. The porins (PorA and PorB), and opacity protein (Opa) are also involved in adhesion to endothelial cells.
  3. Lipooligosacchariide (LOS) binds to monocytes and dendritic cells to trigger the release of cytokines. This results in endothelial damage and capillary leakage.
  4. This activates host signalling pathways, opening intracellular junctions.
  5. Meningococcus passes through and proliferates to cause infection.
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