Streptococcus pneumoniae

Question 1

Type

Answer 1

Gram+ cocci
Arranged in pairs
or chains
- catalase
negative
- nonmotile
- facultative
anaerobe

Question 2

Features

Answer 2

• Hemolytic activity on
  sheep blood agar: a,B,Y
• Lancefield
  Grouping(polysaccharide
  antigen in cell wall) : 21
• M protein: S.pyogenes

Question 3

Pathogenesis

Answer 3

16s rRNA sequencing
- Pyogenic group
- Mutans group: Dental
caries
- Mitis group: subacute
IE
● Polysaccharide
capsule: Hyaluronic
acid(anti-phagocytic)

Question 4

Diagnostic

Answer 4

Quellung
Reaction:
Serotyping of
S.pneumoniae
- Not specific
- Ab-Ag
test;capsule has
Ag→ react with
anti-serum →
Swell→ stain
bacteria with
methylene blue