Lecture 10 - Neisseria

Question 1

Name the two important species of Neisseria human pathogens

Answer 1

1. N. meningitidis

2. N. gonorrhoeae

Question 2

What type of oxygen dependence do Neiserria have?

Answer 2

Aerobic or Microaerophilic (mostly microaerophilic)

Question 3

What kind of infections do they cause?

Answer 3

Purulent infections (pus forming)

Question 4

T or F, Neisseria are Gram negative diplocci

Answer 4

True

Question 5

Where is the typical place to find Neisseria?

Answer 5

Nasopharynx (mouth and upper respiratory tract)

Question 6

Name the 4 virulence factors for N. Meningtidis

Answer 6

1. Fimbrae (Allow attachment and resist phagocytosis)
2. Capsule (Anti-phagocytic, Ag differences)
3. IgA Protease
4. ‘Blebs’ of LPS

Question 7

How is N. meningitidis spread?

Answer 7

Spread by respiratory droplets typcially among individuals with prolonged contact

Question 8

What is the only natural carrier of N. meningitidis?

Answer 8

Humans

Question 9

N. meningitidis is primarily a disease of what age group? Why?

Answer 9

Young children
No Abs to opsonize strain, major window of opportunity as maternal IgG levels decline and humoral immunity is still developing

Question 10

What 2 major diseases are caused by N. meningitidis?

Answer 10

1. Meningococcal Sepsis (Meningococcemia)

2. Meningitis

Question 11

Describe the mode of action in Meningococcemia?

Answer 11

Encapsulated strains move across lining of nose and throat into blood.
Rapidly multiply and release large quantities of endotoxin (blebs)
Endotoxins activate monocytes to produce large amounts of cytokines that result in SYSTEMIC inflammation and potentially septic shock

Question 12

Describe the mode of action in Meningitis?

Answer 12

Bacteria do not grow rapidly in blood and have time to cross blood into fluid and membranes surrounding the brain.
Endotoxin is secreted and stimulates inflammatory cascade locally in CNS tissues and systemically which results in symptoms/signs of meningitis

Question 13

Which is more common, meningitis or meningococcemia?

Answer 13

Meningitis

Question 14

What is the treatment for N. meningitidis?

Answer 14

Vaccination
Antimicrobial prophylaxis
Stay away from crowded conditions where it can be transmitted easily.

Question 15

Major cause of spread of this N. meningitidis?

Answer 15

Huge amounts of blebbed endotoxin released by N. memingitidis

Question 16

How common a STI is N. gonorrhea

Answer 16

2nd most common STI in U.S.

Question 17

Name the 6 virulence factors to N. gonorrhea

Answer 17

Fimbrae
Local LPS
IgA Protease
Ag-variation of pili structure (gene conversion and phase variation)
Surface receptors for host proteins
Penicillin resistance

Question 18

The virulence factors for N. gonorrhea are broken up into what 3 main categories?

Answer 18

1. Attachment factor
2. Damaging factors
3. Avoidance Factors

Question 19

How is N. gonorrhea spread?

Answer 19

Primarily by sexual contact. Only in humans. No other known resevoir

Question 20

Are symptoms of N. gonorrhea infection more common in men or women?

Answer 20

Men are symptomatic while women are commonly asymptomatic or with mild symptoms

Question 21

Do men or women have a greater risk of being infected with N. gonorrhea

Answer 21

Women have 50% chance. Men 25% chance. This is due to the larger epithelial area in vagina

Question 22

Women who are infected with UNTREATED gonorrhea develop what?

Answer 22

PID (Pelvic Inflammatory Disease)

Question 23

What is a treatment for N. gonorrhea

Answer 23

No current vaccine because of Ag-variation of bacterial surface epitopes
Penicillin is no longer used because gonorrhea bacterium have become resistant

Question 24

Are newborns at risk for infection if their mother has N. gonorrhea infection?

Answer 24

Yes, they are typically treated with anti-microbial eye ointment to prevent eye infections of this bacteria

Question 25

3 major consequences of PID

Answer 25

Sterility
Ectopic Pregnancy
Pelvic surgery