Kirchner Medium Base is supplied by HiMedia. It is a sterile ready prepared media containing 5ml of light amber coloured clear solution in bottles. Kirchner Medium Base is generally used as a Poctri supplement (containing Polymyxin B, Amphotericin B, Carbenicillin & Trimethoprim). It is advisable to store this ready prepared media between 2-8C. Composition (in gm/L) is as follows:

Disodium phosphate (3.00)

Monopotassium phosphate (4.00)

Magnesium sulphate (0.60)

Sodium citrate (2.50)

L-Asparagine (5.00)

Horse serum (100.00)

Kirschner Medium was designed by Kirschner based on the formulation of Longs Medium and further modified with addition of glycerol and enrichments for the cultivation of M. tuberculosis. This medium is widely used for antibacterial test, for antituberculotic agents and sometimes in differential culture of M. tuberculosis from unhealthy materials. Kirschner Semisolid Agar Medium is obtainable by adding up to 0.1% agar. In case of screening test for antituberculotic agents on solid media, it takes at least 3-4 weeks to achieve culture of tubercle bacilli. Broth medium can give results in a week or two; hence broth medium is widely used in cases where rapid results are needed. Kirschner medium contains two phosphates, a sulphate and citrate, which buffer the medium. Hence the medium can be directly inoculated without any prior neutralization. L-asparagine in the medium supports the growth of M. tuberculosis, as it is a good nutrient for the organism. Horse serum also promotes the growth of the organism. Penicillin inhibits the growth of contaminating bacteria. At first stage after inoculation of M. tuberculosis, granular colonies are observed at the bottom of the tube and as the incubation proceeds bacterial film will be formed on the surface, rendering the medium transparent.