Middlebrooks 7H11 Selective Agar (No Glycerol)

This is an agar-based medium for the isolation of Mycobacterium spp. from veterinary samples; particularly the species primarily responsible for bovine TB, M.bovis. The medium is complex but includes L-Glutamic acid, Ammonium sulphate, Sodium citrate, Pyridoxine and Biotin as growth factors and Magnesium sulphate, Ferric ammonium citrate as sources of trace ions. Di-sodium phosphate and Mono-potassium phosphate are also present to maintain the pH of the medium. Further enrichment is provided by the addition of Oleic acid, Albumin and Dextrose. The medium is made selective by the inclusion of Ticarcillin, Polymyxin B, Trimethoprim and Amphotericin B. Malachite green is also incorporated to provide a colour contrast between the colonies and the medium as well as contributing some inhibitory effect on organisms other than mycobacteria. It should be noted that Glycerol is NOT added to this medium as Glycerol can be inhibitory for M.bovis when examining veterinary samples. However, this product contains Lysed sheep blood, Adult bovine serum and Sodium pyruvate to enhance the growth of M.bovis.