Streptococcus pneumoniae
Infections and Diseases
Grayish or translucent
- Mucoidal (if encapsulated)
- Encapsulated strains produce a thick polysaccharide
layer that gives the colony a shiny, and wet appearance
on agar plates.
- Rough (if non-encapsulated) Alpha-Hemolysis
Produces greenish zone on blood agar due to partial RBC breakdown
Aerobic & Facultative Anaerobic
Morphological Details
Diplococcus (spherical)
Pairs of Cocci
Gram-positive
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Identifiable Physical Features
Circular & Convex Small, 0.5–1.25 mm in diameter
Grayish or translucent
- Mucoidal (if encapsulated)
- Encapsulated strains produce a thick polysaccharide
layer that gives the colony a shiny, and wet appearance
on agar plates.
- Rough (if non-encapsulated) Alpha-Hemolysis
Produces greenish zone on blood agar due to partial RBC breakdown
Aerobic & Facultative Anaerobic
Additional Facts
Antibiotic resistance concerns:
- Penicillin resistance is increasing in hospital-acquired strains
Vaccine:
- Prevnar 13 and Pneumovax 23
Used in the famous Griffith experiment in 1928, which led to the discovery of DNA as genetic material
