Blood agar is used by inoculating the surface of the agar with a clinical sample. After incubation, the growth characteristics and hemolytic patterns are examined. There are three main types of hemolysis observed on blood agar:
Alpha-hemolysis: Partial hemolysis causing a greenish discoloration around colonies. Beta-hemolysis: Complete hemolysis resulting in a clear zone around colonies. Gamma-hemolysis: No hemolysis, with no change in the agar around colonies.
These observations help identify specific bacteria, such as Streptococcus pyogenes, which exhibits beta-hemolysis.
