Neisseria

Question 1

What are two most clinically important species of Neisseria?

Answer 1

N. meningitidis

N. gonorrhoeae

Question 2

What is the morphology of Neisseria?

Answer 2

Gram negative diplococci

Question 3

Which species of Neisseria have a polysaccharide capsule?

Answer 3

N. meningitidis

Question 4

On what medium can you grow Neisseria?

Answer 4

Thayer-Martin agar

Question 5

What are the two major clinical diseases caused by N. meningitidis?

Answer 5

Meningitis

Meningococcemia

Question 6

What is the clinical presentation of meningococcemia?

Answer 6

Bacteremia/sepsis
Rash with petechial lesions on body
- can get gangrenous, lead to amputation
Can progress to shock rapidly (DIC, hypotension, hemorrhage, organ failure)

Question 7

What particular immune deficiency is a risk factor for meningococcal disease due to N. meningitidis?

Answer 7

Complement deficiency

- Or having too much Complement Factor H

Question 8

What cell does N. meningitidis bind to?

Answer 8

Non-ciliated epithelial cells in nasal pharynx

Question 9

What is the pathogenesis of N. meningitidis?

Answer 9

Binds non-ciliated epithelial cells in nasal pharynx
Passes through cells, disseminates via blood stream
Crosses BBB to initiate meningitis via inflammatory response

Question 10

What are the virulence factors of N. meningitidis?

Answer 10

• Polysaccharide capsule
• Type IV pili
• LOS endotoxin
• Complement factor H binding protein

Question 11

What other organism expresses a Type IV bundle forming pillus?

Answer 11

EPEC

Question 12

How does complement factor H binding protein act as a virulence factor?

Answer 12

N. meningitidis can bind complement Factor H

Factor H prevents complement from attacking

Question 13

What is treatment of choice for meningitis due to N. meningitidis?

Answer 13

Ceftriaxone

Rifampin for prophylaxis for contacts

Question 14

Why is there no vaccine to serogroup B of N. meningitidis?

Answer 14

Because group B has polysialic acid

Since humans have sialic acid on our own cells, can’t target that

Question 15

What is the morphology of Kingella?

Answer 15

Gram neg aerobic coccobacilli

Question 16

What is the clinical presentation of Kingella?

Answer 16

Infectious arthritis of children

Question 17

What is the treatment for Kingella?

Answer 17

Ampicillin or ceftriaxone

Question 18

What is a common complication of N. gonorrhoeae infection in women?

Answer 18

Pelvic inflammatory disease (ascending infection from cervix)

Question 19

What is the pathogenesis of N. gonorrhoeae?

Answer 19

Similar to meningitidis, but less virulent (no polysaccharide capsule)
Attaches to genitourinary epithelium via pili
Crosses epithelium but dissemination rare
Can survive within neutrophils!

Question 20

What are major virulence factors of N. gonorrhoeae?

Answer 20

Pili (adherence)
Por (porin)
Opa (adherence factor, suppresses lymphocytes)
LOS
Fe-binding proteins

Question 21

Why does N. gonorrhoeae need mechanisms of protection from immune response?

Answer 21

Needs to survive long enough until next sexual encounter and transmission to next partner

Question 22

What are mechanisms of protection from immune response for N. gonorrhoeae?

Answer 22

• Antigenic and phase variation (variable antigenic targets of immune response and can switch expression on or off; makes it difficult to generate antibodies against)
• LOS sialylation (protects against bactericidal antigens)

Question 23

What is the treatment of choice for N. gonorrhoeae infection?

Answer 23

Cefixime or ceftriaxone (both 3rd gen cephalosporins)

Often give doxycycline also (to treat Chlamydia co-infection)

Question 24

Why is antibiotic resistance becoming such a big problem for Neisseria infections?

Answer 24

Mtr efflux pump pumps out antibiotics