||The English used in this article or section may not be easy for everybody to understand. (May 2012)|
|SEM micrograph of S. pneumoniae.|
Streptococcus pneumoniae, or pneumococcus, is a gram-positive, alpha-hemolytic diplococcus aerotolerant anaerobe and a member of the genus Streptococcus. An important human pathogen, S. pneumoniae was recognized as a major cause of pneumonia in the late 19th century and is the subject of many humoral immunity studies.