A genus of grampositive, facultatively aerobic cocci (family Streptococcaceae) occurring in pairs or chains.
It is separable into the pyogenic group, the viridans group, the enterococcus group, and the lactic group.
- The first group includes the betahemolytic human and animal pathogens
- the second and third include alphahemolytic parasitic forms occurring as normal flora in the upper respiratory tract and the intestinal tract, respectively; and the fourth is made up of saprophytic forms.
Streptococcus pneumoniae a small, slightly elongated, encapsulated coccus, one end of which is pointed or lanc shaped;
the organisms commonly occur in pairs. This is the most common cause of lobar pneumonia, and it also causes serious forms of meningitis, septicemia, empyema and peritonitis. There are some 80 serotypes
distinguished by the polysaccharide hapten of the capsular substance. also Called pneumococcus.
Streptococcus pyo'genes a beta-hemolytic, toxigenic, pyogenic species that causes septic sore throat, scarlet fever, rheumatic fever, puerperal fever, acute glomerulonephritis, and other conditions in humans.
