What is Streptococcus pneumoniae?
Streptococcus pneumoniae (S. pneumoniae or “pneumococcus”) is a bacterium commonly found in the nasopharynx (back of the nose) of healthy people. More than 90 serotypes of S. pneumoniae have been identified. Serotypes of pneumococcus are identified on the basis of differences in the polysaccharide (sugar) capsule of the organism. The presence of pneumococcus in the nasopharynx is referred to as “carriage”. Most people have been carriers of S. pneumoniae at some point in their lives. Pneumococcal carriage is more common in young children, is usually transient and generally causes no illness. S. pneumoniae is an exclusively human pathogen and is spread from person-to-person by respiratory droplets, meaning that transmission generally occurs during coughing or sneezing to others within 6 feet of the carrier. Thus, carriers of S. pneumoniae, while generally healthy, are an important source of infection and disease for others. Occasionally, S. pneumoniae will spread from the nasopharynx of
