In 1955, Leavitt et al.4 discovered Tryptic Soy Agar (TSA) facilitated vigorous growth of aerobic and anaerobic microorganisms. TSA, a general purpose medium, is commonly referred to as Soybean-Casein Digest Agar USP 23. TSA is a nutritious base, and a variety of supplements can be added to enhance this medium. The addition of 5% sterile, defibrinated sheep, horse, or rabbit blood provides an excellent non-selective medium, used to determine hemolytic reactions of bacteria. TSA supplemented with lecithin and Tween 80® is widely used in environmental monitoring.5
TSA is recommended in multiple water & wastewater applications,6 and numerous standard methods for food testing.7 This medium also conforms to Harmonized United States Pharmacopoeia (USP), European Pharmacopoeia (EU), and Japanese Pharmacopoeia (JP).1,2,3 Clinically, TSA is used in the differentiation of Haemophilus species (the X and V factors are omitted from this medium), and widely used for blood cultures. TSA is commonly used as a maintenance medium for culture collections, and testing bacterial contaminants in cosmetics.8
1. United States Pharmacopeial Convention. 2007. The United States pharmacopeia, 31st ed., Amended Chapters 61, 62, 111. The United States Pharmacopeial Convention, Rockville, MD.
2. Directorate for the Quality of Medicines of the Council of Europe (EDQM). 2007. The European Pharmacopoeia, Amended Chapters 2.6.12, 2.6.13, 5.1.4, Council of Europe, 67075 Strasbourg Cedex, France.
3. Japanese Pharmacopoeia. 2007. Society of Japanese Pharmacopoeia. Amended Chapters 35.1, 35.2, 7. The Minister of Health, Labor, and Welfare.
4. Leavitt, J. M., I. J. Naidorf and P. Shugaevsky. 1955. The undetected anaerobe in endodontics: a sensitive medium for detection of both aerobes and anaerobes. The NY J. Dentist. 25:377-382.
5. Orth, D. S. 1993. Handbook of cosmetic microbiology. Marcel Dekker, Inc., New York, NY.
6. Greenberg, A. E., L. S. Clesceri, and A. D. Eaton (eds.). 1995. Standard methods for the examination of water and wastewater, 19th ed. American Public Health Association, Washington, D.C.
7. U.S. Food and Drug Administration. Bacteriological analytical manual, 8th ed., AOAC International, Gaithersburg, MD.
8. Curry, A. S., G. G. Joyce, and G. N. McEwen, Jr. 1993. CTFA Microbiology guidelines. The Cosmetic, Toiletry, and Fragrance Association, Inc. Washington, D.C.