General Information: Streptococcus pneumoniae Taiwan19F is one of the most common Streptococcus pneumoniae serotypes in Asia. Most isolates of serotype 19 are resistant to penicillin. This organism is a member of the normal human nasopharyngeal flora. There are more than 85 different antigenic types of S. pneumoniae, which are classified based on their capsule antigens. This organism is also the most common cause of sinusitis, acute bacterial otitis media, and conjunctivitis beyond early childhood. S. pneumoniae is also known to cause pneumonia, meningitis, and bacteremia. Streptococci are Gram-positive, non-motile, non-spore forming, catalase-negative cocci that occur in pairs or chains. Members of this genus vary widely in pathogenic potential. Most streptococci are facultative anaerobes, and some are obligate anaerobes.