streptococci have been grouped by
the phenotypic characteristics of hemolysis
and
Lancefield antigen composition
as
well as by pathogenic potential.

Streptococci can be either beta‐hemolytic (complete hemolysis),
alpha‐hemolytic (incomplete hemolysis)
resulting in a green zone around the colony), or
gamma‐hemolytic (no hemolysis) on blood agar.

he Lancefield system, depending on the cell
wall carbohydrate (Lancefield antigen) or
lipoteichoic acid
(group D), some of the streptococci have
been placed in groups A, B, C, D, F, and G