BLOOD AGAR BASE (INFUSION AGAR)

Blood Agar Base is a nutrient-rich medium for isolation and cultivation of fastidious pathogenic microorganisms after supplementation with blood. It also can be used as a general purpose medium but without blood enrichment. The medium is useful for primary isolation of Haemophilus species and allows demonstration of characteristic hemolytic reactions produced by microorganisms.
Fresh defibrinated sheep blood is added to stabilize the medium at approximately pH 6.8 and to provide suitable conditions for clear hemolysis zones. Sheep blood is especially helpful when demonstrating hemolysis by Group A Streptococci. Horse blood will support growth and hemolysis of Haemophilus haemolyticus. The colonies produced may resemble those produced by Streptococcus pyogenes and this makes it important to interpret them correctly.
Tryptone and Brain Heart Infusion contain amino acids, minerals and other essential growth factors necessary for the growth of microbes. Sodium chloride maintains the osmotic balance, and agar is the solidifying agent. The rich nutrient base, coupled with the addition of blood, renders this select medium suitable for the routine isolation and differentiation of clinically significant organisms according to their hemolytic patterns.

Suitable for cultivating fastidious pathogenic microorganisms after blood enrichment, while supporting hemolysis observation and routine isolation of relevant bacterial species.