<unk><unk> , or pneumococcus, is a Gram-positive bacterium. It is a diplococcus, alpha-hemolytic member of the<unk>  genus.  During the 19th century<unk> was heavily associated with this pathogen. S.<unk>  is known to be the cause of various different infections apart from<unk> including  endocarditis, meningitis, pericarditis, brain abscess, otitis media, osteomyelitis, acute sinusitis, septic arthritis, peritonitis, and cellulitis. In children as well as adults,  S.<unk>  is the most common cause of otitis media as well as bacterial meningitis.<unk> caused by S.<unk>  is usually found at the extremes of the age (in old or very young individuals).<unk>  viridans also belongs to the family of alpha hemolytic bacteria but can e distinguished from S.<unk>  by an optochin test.<unk>  viridans are found to be insensitive to optochin where as S.<unk>  are found to be optochin sensitive. The most potent virulence factor of S.<unk>   is its polysaccharide capsule. Up to 91 various types of capsules have been discovered; each of these differ in virulence, drug resistance, prevalence, and distribution.
Streptococcus pneumoniae infection
Haemophilus influenzae infection
Pneumococcal infections
Middle East respiratory syndrome coronavirus infection
Group B streptococcal infection
Group A streptococcal infection
COVID-19-associated neutrophilia
Lemierre's syndrome