Lecture 10 - Neisseria Flashcards Preview

Medical Microbiology > Lecture 10 - Neisseria > Flashcards

Flashcards in Lecture 10 - Neisseria Deck (25):
1

Name the two important species of Neisseria human pathogens

1. N. meningitidis
2. N. gonorrhoeae

2

What type of oxygen dependence do Neiserria have?

Aerobic or Microaerophilic (mostly microaerophilic)

3

What kind of infections do they cause?

Purulent infections (pus forming)

4

T or F, Neisseria are Gram negative diplocci

True

5

Where is the typical place to find Neisseria?

Nasopharynx (mouth and upper respiratory tract)

6

Name the 4 virulence factors for N. Meningtidis

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

7

How is N. meningitidis spread?

Spread by respiratory droplets typcially among individuals with prolonged contact

8

What is the only natural carrier of N. meningitidis?

Humans

9

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

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

10

What 2 major diseases are caused by N. meningitidis?

1. Meningococcal Sepsis (Meningococcemia)
2. Meningitis

11

Describe the mode of action in Meningococcemia?

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

12

Describe the mode of action in Meningitis?

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

13

Which is more common, meningitis or meningococcemia?

Meningitis

14

What is the treatment for N. meningitidis?

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

15

Major cause of spread of this N. meningitidis?

Huge amounts of blebbed endotoxin released by N. memingitidis

16

How common a STI is N. gonorrhea

2nd most common STI in U.S.

17

Name the 6 virulence factors to N. gonorrhea

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

18

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

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

19

How is N. gonorrhea spread?

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

20

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

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

21

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

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

22

Women who are infected with UNTREATED gonorrhea develop what?

PID (Pelvic Inflammatory Disease)

23

What is a treatment for N. gonorrhea

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

24

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

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

25

3 major consequences of PID

Sterility
Ectopic Pregnancy
Pelvic surgery