Streptococcus pneumoniae

General:

Clinical:

• Normal: Respiratory flora.
• Abnormal: Community acquired pneumonia, bacteremia, endocarditis, meningitis, sinusitis, otitis media.

Resistance: Developing resistance to penicillins.

Morphology: Gram+ lancet-shaped cocci usually seen in pairs, some strains encapsulated.

Growth characteristics: Alpha-hemolytic mucoid colonies (later become concave or punched-out) on blood agar preferably at 5% CO2. Over 80 serotypes; capsular swelling in presence of type-specific antibody is called a quellung reaction.

Common/important pathogens: