Description
These media are prepared by completely replacing animal based peptone with vegetable peptone making the media free of BSE / TSE risks. Rosenow devised the original medium by adding brain tissue to dextrose broth. These media like the conventional media are nutritious and well buffered to support the growth of wide variety of microorganisms. With the addition of 10% defibrinated sheep blood, it is useful for isolation and cultivation of Histoplasma capsulatum and other fungi. In the formulation containing 6.5% sodium chloride, the salt acts as a differential and/or selective agent by interfering with membrane permeability and osmotic and electrokinetic equilibria in salt intolerant organisms. The addition of 0.1% agar improves growth of microaerophilic and anaerobic microorganisms. Brain Heart Infusion Broth, Veg with addition of 1.5% agar should not be used for detection of haemolytic activity of Streptococci, since it contains dextrose, which has been reported to cause a typical haemolytic reactions when it is present in blood containing media. For selective isolation of fungi, addition of Gentamicin and/or Chloramphenicol is recommended.
