Unlike the exotoxins of S. pyogenes however, pneumolysin is released only when SP cells are lysed. Antibodies against pneumolysin conger partial protection. While more than 80 serotypes have been defined, the majority of disease caused by a limited number of serotypes. Transmission occurs for person to person by direct contact with respiratory droplets. Viral infections may precede and predispose individuals to pneumococcal infection.
Lobar consolidation is common.
Patients generally appear acutely ill with signs of consolidation on pulmonary examination. Clinical response to antibiotics is generally prompt within 12-36 hours. Recovery is associated with an abrupt fall in temperature, also known as crises. Meningitis SP is the most common cause of bacterial meningitis. Pneumococcal meningitis is associated with a high incidence of morbidity and mortality.