What is Streptococcus pneumoniae?

Streptococcus pneumoniae (pneumococcus) is a leading cause of pneumonia, meningitis and otitis media; its polysaccharide capsule defines more than 90 serotypes and is the basis of vaccines.

It spreads by respiratory droplets. Anti-capsular and anti-pneumococcal-protein (e.g. PspA) antibody assays underpin vaccine immunogenicity and serotype research.

Transmission & symptoms

Streptococcus pneumoniae (pneumococcus) spreads by respiratory droplets and causes pneumonia, meningitis, bacteraemia and otitis media. Its polysaccharide capsule defines more than 90 serotypes and is the target of pneumococcal vaccines.

Diagnosis & serology

Immunity is measured as serotype-specific anti-capsular IgG (and opsonophagocytic activity), the correlates used for pneumococcal conjugate and polysaccharide vaccines. ELISA quantifies these responses.

Research applications

Research tools cover capsular and protein antigens (e.g. PspA), host receptors (the platelet-activating-factor receptor, polymeric immunoglobulin receptor), complement and acute-phase markers such as CRP.