H. Flu and Neisseria Meningitidis Flashcards Preview

POD Exam II > H. Flu and Neisseria Meningitidis > Flashcards

Flashcards in H. Flu and Neisseria Meningitidis Deck (24):
1

Growth requirements for H. influenzae:

- Hemin or X factor.
- NAD or V factor.
- Heated blood agar (chocolate).

2

H. influenzae strains without capsule cause:

Mucosal infections:
- Otitis media.
- Sinusitis.
- Bronchitis.
- Pneumonia.

3

H. influenzae capsules are composed of:

Polyribitol phosphate. PRP.

4

H. influenzae strain that accounts for majority of invasive disease:

Hib

5

H. influenzae strains with a capsule cause:

Invasive infections:
- Meningitis.
- Epiglottitis.
- Etc.

6

H. influenzae colonization (6):

1. Outer membrane proteins (OMP) P2 and P5 promote bacterial binding to mucus.
2. LPS damages ciliated cells.
3. Adhesins and pili mediate direct adherence to non-ciliated epithelial cells.
4. IgA proteases cleave IgA.
5. Invasion into cells and subepithelial space.
6. Binding and uptake of iron and heme allow organisms to persist.

7

Encapsulated H. influenzae strains invade mucosa by:

Separating apical tight junctions of columnar epithelium and moving intercellularly.

8

Major H. influenzae virulence factor:

Polysaccharide capsule.

9

Severity of H. influenzae infection is related to:

Rate of clearance of bacteria.

10

Patients with higher risk for H. influenzae meningitis and epiglottitis (3):

- Pts with no anti-PRP antibodies.
- Complement deficiency.
- Post-splenectomy.

11

Ages of highest risk of H. influenzae infection:

6-18 months.

12

H. influenzae meningitis symptoms:

Younger children:
- Nonspecific signs and symptoms.
- 1-3 day history of mild upper respiratory disease.
- Irritability, fever, lethargy.
Older children may have:
- HA.
- Photophobia.
- Meningismus.

13

H. influenzae arthritis:

- Leading cause of septic arthritis in children < 2.
- Most often affects single large joint.
- Due to bacteremic spread.
- Presents with fever, decreased ROM, warmth and swelling.
- Req's surgical drainage and IV antibiotic therapy.

14

H. influenzae stain:

Gram negative rods.

15

Satellite phenomenon:

Staph aureus excretes NAD allowing H. flu to grow as small colonies.

16

H. influenzae treatment:

- 3rd gen cephalosporins for serious infections.
- PCN + beta-lactamase inhibitor.

17

Antibiotic prophylaxis for H. influenzae:

Rifampin.

18

Neisseria meningitidis (5):

- Non-motile.
- Aerobic.
- Gram - diplococci with flattened sides.
- Complex growth req's: chocolate agar.
- Oxidize carbohydrates.

19

N. meningitidis virulence factors (6):

- Polysaccharide capsule.
- Pili.
- Porin proteins.
- LOS.
- IgA protease.
- Transferrin binding proteins.

20

N. meningitidis porin channel PorB (3):

- Interferes with degranulation of neutrophils.
- Facilitates invasion to epithelial cells.
- PIA antigen makes bacteria resistant to complement-mediated killing.

21

N. meningitidis LOS (4):

- Composed of lipid A and core oligosaccharide.
- Lacks the O-antigen polysaccharide of LPS.
- Lipid A possesses endotoxin activity.
- Neisseria release outer membrane blebs during rapid cell growth.

22

N. meningitidis transferrin binding proteins (2):

- Binds human transferrin.
- Allows bacteria to compete with host for iron.

23

N. meningitidis meningococcemia (4):

- Short hx of URI symptoms, fever and rash.
- Severe circulatory collapse with DIC and thrombosis of small blood vessels.
- Purpura and shock can occur within hours.
- Shock and DIC --> destruction of adrenal glands --> Friderichsen syndrome.

24

N. meningitidis diagnosis (2):

- Microscopy: readily seen in CSF.
- Culture = gold standard for diagnosis.