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Flashcards in Neisseria Deck (26):
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Where is N.meningitidis found?

Nasopharynx of humans ONLY. Strict human parasite.

1

Can immunity be developed to N.meningitidis?

Yes, to particular strains.

2

How does N.meningitidis spread?

By respiratory transmission.

3

What is the morphology of N.meningitidis?

1. Kidney bean shaped with concave sides, facing each other (doughnut appearance).
2. Gram(-) diplococci.

4

What is the metabolism of N.meningitidis?

1. Facultative anaerobe
2. Grows best in high CO2 environment.
3. Ferments maltose + glucose (m + g are in meningitidis).

5

What is the virulence of N.meningitidis?

1. Capsule
2. IgA1 protease
3. Unique proteins that can extract iron
4. Pili for adherence

6

What are the main serotypes of N.meningitidis capsule?

13 serotypes based on antigenicity of capsule polysaccharides.

7

What serotypes of N.meningitidis are associated with epidemics of meningitis?

A,B,C - usually type B.

8

What are the toxins of N.meningitidis?

1. Endotoxin: LPS
2. No exotoxins

9

What can N.meningitidis cause?

1. Meningitis
2. Septicemia (meningococcemia)

10

How can we identify N.meningitidis?

1. Gram stain
2. Culture:
- Chocolate agar
- Thayer Martin VCN
- Cell wall contain cytochrome oxidase which oxidizes dye tetramethylphenylene diamine from colorless to deep pink.
- PCR

11

What is important to keep in mind about N.meningitidis?

1. Neonates (6-24months) are very susceptible, when protective IgG is low.
2. Army recruits are also at high risk (with carriage rates of greater than 40%).

12

Where is N.gonorrhoeae found?

Humans only - no immunity to repeated infections.

13

How is N.gonorrhoeae transmitted?

Sexually

14

What is the morphology of N.gonorrhoeae?

The same as N.meningitidis.

15

What is the main metabolic difference between N.meningitidis and N.gonorrhoeae?

N.gonorrhoeae ferments only glucose, not maltose. (g is in gonorrhoeae)

16

What is the virulence of N.gonorrhoeae?

1. Pili
2. IgA1 protease
3. Outer membrane proteins
4. Unique proteins that can extract iron from transferrin, lactoferrin and Hb.

17

How do the pili of N.gonorrhoeae function as a virulent factor?

1. Adherence to epithelial cells
2. Antigenic variation
3. Antiphagocytic - binds bacteria tightly to host cell, protecting it from phagocytosis

18

What are the virulent outer membrane proteins of N.gonorrhoeae?

Protein I --> porin.
Protein II (opacity protein) --> presence associated with dark, opaque colonies - for adherence.

19

What are the toxins of N.gonorrhoeae?

LPS endotoxin - no exotoxin.

20

What can N.gonorrhoeae cause?

Men: urethritis
Women: cervical gonorrhea, which can progress to PID
Both:
1. Gonococcal bacteremia
2. Septic arthritis
Neonates: Ophthalmia neonatorum conjunctivitis in newborns.

21

How do we identify N.gonorrhoeae?

Same way as with N.meningitidis.

22

What is important to keep in mind about N.gonorrhoeae?

No immunity followin infection: a person can be reinfected numerous times.

23

Where is Moraxella (Branhamella) catarrhalis found?

Normal respiratory flora.

24

What can M.catarrhalis cause?

1. Otitis media in children
2. Respiratory tract infections - sinusitis, bronchitis, pneumonia.
3. COPD exacerbations

25

What is important to keep in mind about M.catarrhalis?

It is resistant to penicillin.