Streptococcus<unk>  is an unofficial name applied to a<unk>  of basically similar viridans streptococci species showing various hemolytic, serological, and physiological characteristics. The species name Streptococcus anginosus has recently been recognized as the approved name for these organisms. They have been implicated as etiologic agents in a variety of serious purulent infections, but because of their heterogeneous characteristics, these organisms may be unrecognized or misidentified by clinical laboratorians.
The unique characteristic of them from other pathogenic streptococci, such as S. pyogenes and S. agalactiae, is their ability to cause abscesses.
Streptococcus milleri group
Streptococcus anginosus
HACEK organism
Haemophilus influenzae biogroup aegyptius
Enterococcus faecium
Staphylococcus haemolyticus
Clostridium sordellii
Pseudomonas aeruginosa