Blood Agar Base + Nalidixic Acid is a modification of Blood Agar Base with the addition of nalidixic acid as an inhibitor of the accompanying flora. Nalidixic acid blocks the DNA replication of susceptible bacteria and acts against many Gram-negative bacteria. The Heart infusion and Meat peptone are rich sources of nitrogen, vitamins, minerals and amino acids essential for growth. Sodium chloride supplies essential electrolytes for transport and osmotic balance. The blood is an additional source that provides growth factors for the microorganisms and is the basis for determining hemolytic reactions. Hemolytic patterns may vary with the type of blood or base medium used. For example, defibrinated sheep blood gives best results for Group A streptococci. Bacteriological agar is the solidifying agent. Streptococcal colonies will be 2-3 mm of diameter; colorless or smooth, round, white and will produce a- hemolysis (Streptococcus pneumoniae), ÃŸ (Streptococcus pyogenes) alpha or negative (Streptococcus bovis).
Write Your Own Review