Streptococcus Pneumoniae

Question 1

General Characteristics

Answer 1

Diplococcus, Alpha-hemolytic (partially lyse RBCs)

Question 2

Incubation period

Answer 2

1-3 days

Question 3

Significance

Answer 3

Bacterium most commonly found in human pneumonia

Commonly responsible for typical lobular pneumonia, otitis media, meningitis, bacteremia.

Affects lobular part of lung or the bronchis.

Question 4

Transmission

Answer 4

Respiratory Droplets

Question 5

Pathogenesis

Answer 5

Primary virulence factor: polysaccharide capsule (antiphagocytic)
1.) Releases Hemolysin (pneumolysin) that damages respiratory epithelium
2.) Alveoli responds with a build up of fluid, RBCs, and WBCs leading to productive cough (blood-tinged, pink or rusty sputum)
3.) Organism disseminates into lymphatics, blood, and other tissues.

Question 6

Diagnosis

Answer 6

Clinical Suspicion
Optochin sensitivity
Lysed by bile
Quellung reaction (detects capsule)
Gram stain (positive)

Question 7

Treatment

Answer 7

Penicillin
Vancomycin

Question 8

Prevention

Answer 8

Pneumococcal conjugate vaccine against capsule.