What type of hemolysis is exhibited by Strep pneumoniae?

Streptococcus pneumoniae is known for exhibiting alpha hemolysis on blood agar plates. This type of hemolysis is characterized by a partial breakdown of red blood cells, leading to a greenish discoloration around the bacterial colonies due to the conversion of hemoglobin to methemoglobin. This characteristic is important in the laboratory diagnosis of Streptococcus pneumoniae, as it distinguishes this organism from others in the Streptococcus genus.

Alpha hemolytic streptococci are typically found in the mouth and upper respiratory tract and are a common part of the normal flora, but can also cause opportunistic infections, including pneumonia, particularly in immunocompromised individuals. The other types of hemolysis refer to different processes: beta hemolysis involves complete lysis of red blood cells and appears clear around the colonies, gamma hemolysis indicates no lysis or change in color around the colonies, and delta hemolysis is not a standard classification in typical hemolysis discussions. Understanding these patterns is crucial for clinical diagnostics and guiding appropriate treatment.