Neisseria

Question 0

Can immunity be developed to N.meningitidis?

Answer 0

Yes, to particular strains.

Question 1

Where is N.meningitidis found?

Answer 1

Nasopharynx of humans ONLY. Strict human parasite.

Question 2

How does N.meningitidis spread?

Answer 2

By respiratory transmission.

Question 3

What is the morphology of N.meningitidis?

Answer 3

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

Question 4

What is the metabolism of N.meningitidis?

Answer 4

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

Question 5

What is the virulence of N.meningitidis?

Answer 5

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

Question 6

What are the main serotypes of N.meningitidis capsule?

Answer 6

13 serotypes based on antigenicity of capsule polysaccharides.

Question 7

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

Answer 7

A,B,C - usually type B.

Question 8

What are the toxins of N.meningitidis?

Answer 8

1. Endotoxin: LPS

2. No exotoxins

Question 9

What can N.meningitidis cause?

Answer 9

1. Meningitis

2. Septicemia (meningococcemia)

Question 10

How can we identify N.meningitidis?

Answer 10

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

Question 11

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

Answer 11

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%).

Question 12

Where is N.gonorrhoeae found?

Answer 12

Humans only - no immunity to repeated infections.

Question 13

How is N.gonorrhoeae transmitted?

Answer 13

Sexually

Question 14

What is the morphology of N.gonorrhoeae?

Answer 14

The same as N.meningitidis.

Question 15

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

Answer 15

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

Question 16

What is the virulence of N.gonorrhoeae?

Answer 16

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

Question 17

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

Answer 17

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

Question 18

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

Answer 18

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

Question 19

What are the toxins of N.gonorrhoeae?

Answer 19

LPS endotoxin - no exotoxin.

Question 20

What can N.gonorrhoeae cause?

Answer 20

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

Question 21

How do we identify N.gonorrhoeae?

Answer 21

Same way as with N.meningitidis.

Question 22

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

Answer 22

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

Question 23

Where is Moraxella (Branhamella) catarrhalis found?

Answer 23

Normal respiratory flora.

Question 24

What can M.catarrhalis cause?

Answer 24

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

Question 25

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

Answer 25

It is resistant to penicillin.