Brain Heart Infusion Agar

 Principle

• The medium contains protease peptone and infusions from the calf brain and beef heart which serve as sources of carbon, nitrogen, essential growth factors, amino acids, and vitamins.
• Dextrose is used as a source of energy. Disodium phosphate helps in maintaining the buffering action of the medium whereas sodium chloride maintains the osmotic equilibrium of the medium.
• Defibrinated sheep blood added to the basal medium provides essential growth factors for the more fastidious fungal organisms.
• It is highly nutritious and can support the luxuriant growth of a wide variety of microorganisms. It can be further enriched by the addition of blood or rendered selective by adding different antibiotics.
• It is also used in the aminoglycoside and vancomycin screen test for resistant enterococci. BHA with 5-10% sheep blood and chloramphenicol (16 μg/ml) and gentamicin (5 μg/ml) will inhibit the growth of bacteria while allowing the growth of dimorphic fungi.
• This agar can be used as a primary plating medium. This medium is used for the primary isolation of aerobic bacteria from clinical specimens. BHI with 0.5% Polysorbate 80 can be used for detecting Mycobacterium avium-intracellulare complex organisms and M. tuberculosis from blood cultures.

 Use:

Recommended for the cultivation of fastidious pathogenic bacteria, yeasts, and molds.