- Encapsulated, lancet-shaped diplococci
- Virulence factors and resistances
- Capsular polysaccharides
- IgA1 protease
- Treatment
- Penicillin and amoxicillin are traditionally used, but resistance is increasingly common due to altered penicillin-binding proteins (PBPs).
- For severe infections (like meningitis or inpatient pneumonia), ceftriaxone is often used.
- In cases of high resistance, vancomycin is an alternative.
- Prevention
- Pneumococcal Conjugate Vaccine (PCV13, PCV15, PCV20): Polysaccharide conjugated to a carrier protein (diphtheria toxin mutant). Induces T-cell dependent response (IgG). For children <2 yrs and elderly.
- Pneumococcal Polysaccharide Vaccine (PPSV23): Pure polysaccharide capsule. Induces T-cell independent response (IgM). No immunologic memory. For adults <65 with risk factors and all adults >65.