Sheep Blood Agar is used for the isolation, cultivation and detection of hemolytic activity of streptococci and other fastidious microorganisms.
SUMMARY AND EXPLANATION
In a study of viability of streptococci, Snavely and Brahier performed comparative studies of horse, rabbit and sheep blood with Blood Agar Base, and found that sheep blood gave the clearest and most reliable colony and hemolysis characteristics at both 24 and 48 hours. In the course of the investigation, about 1,300 isolations of streptococci were made with Blood Agar Base containing 5% sheep blood.
Peptone and yeast extract provide nitrogen, carbon, amino acids and vitamins in Blood Agar Base. Medium contains sodium chloride to maintain osmotic equilibrium and agar is the solidifying agent.
Supplementation with blood (5-10%) provides additional growth factors for fastidious microorganisms, and is the basis for determining hemolytic reactions. Hemolytic patterns may vary with the source of animal blood.