Streptococcus pneumoniae

Question 1

type

Answer 1

Gram +ve
Diplococcus
Alpha hemolytic
Optochin sensitive
produces green
color - H2O2
oxidize Hgb to
metHb

Question 2

transmission and risk factors

Answer 2

Part of
nasopharyngea
l flora
- no reservoir
Exogenous:
person→
person droplets
- Winter & early
spring
Endogenous:
aspiration

Question 3

most common cause

Answer 3

Most common cause of:
- Meningitis
- Otitis Media
- Pneumonia:
community acquired
- Sinusiits
“MOPS clean RUST”
Rusty sputum: H2O2 oxidized
- Reddish brown sputum or
streaks o

Question 4

pathogenesis

Answer 4

1. Capsule:
   antiphagocytic
2. IgA protease: cleave
   IgA; colonize mucus
   membrane
3. Pneumolysin:
   - Inhibits ciliated
   epithelial cell activity
   - cytotoxic to alveolar
   and endothelial cells
   - Cause inflammation
   - Decrease PMN
   effectiveness
4. Autolysin
5. Transformation:
   acquire DNA from the
   environment

Question 5

diagnostic

Answer 5

Quellung
reaction: 90
serotypes
CXR

Question 6

Polyvalent
capsular
polysaccharide vaccine

Answer 6

Pneumovax,
Pnu-immune
- immunizes
23 most
common
serotypes
For high risk
people:
- Age>65
- Chronic
disease
- HIV
- Alcoholism
-Splenectomy
patients(susc
eptible to
capsulated
organisms:
Neisseria,
Strep,
Haemophilus
B)

Question 7

7 valent
conjugate
vaccine:

Answer 7

T
cell
dependent
response in
children
under 2
years of age