Tryptose Phosphate Broth, 500 g

Tryptose Phosphate Broth is prepared as recommended by APHA (1) for the cultivation of fastidious aerobic bacteria especially Streptococcus species, Listeria and pathogenic Neisseria species. It is also used for antibiotic sensitivity testing by tube method (2). This medium with the addition of agar and sodium azide is used for the isolation of pathogenic Streptococci, Neisseria and other fastidious microorganisms from blood, dairy products (4) and clinical specimens. Tryptose Phosphate Broth with added agar can also be used for emulsification of cheese before isolation of Brucella species (5) and is also recommended by Diagnostic Procedures and Reagents (3). The inclusion of tryptose as nitrogen sources makes this medium highly nutritious. Dextrose serves as the source of fermentable carbohydrate. Sodium chloride maintains osmotic equilibrium. Phosphate salt helps in buffering the medium. The addition of 0.1-0.2 % agar to M093 facilitates anaerobic growth and aids in dispersion of reducing substances and carbon dioxide formed in the environment (2). For blood culture work aseptically add 10 ml of sterile defibrinated blood to 150 ml of sterile medium in 300 ml Erlenmeyer flask. Incubate and subculture on other media. Storage and Shelf-life: Store below 30°C in tightly closed container and the prepared medium at 2-8°C. Use before expiry date on the label. References: 1. American Public Health Association , 1976, Standard Methods for the Examination of Dairy Products, 14th ed., APHA Inc., New York. 2. MacFaddin J., 1985, Media for Isolation-Cultivation-Identification-Maintenance of Medical Bacteria, Vol. I, Williams and Wilkins, Baltimore. 3. American Public Health Association, 1953, Diagnostic Procedures and Reagents, 4th ed., APHA Inc., New York. 4. Newman R.W., 1950, J. Milk Food, Tech., 13 : 226. 5. American Public Health Association, 1953, Standard Methods for the Examination of Dairy Products, 10th ed., APHA Inc., New York.