Middlebrook and Cohn 7H10 Agar, when supplemented with Middlebrook OADC Enrichment, is used in qualitative procedures for the isolation and cultivation of mycobacteria.
- Inorganic salts provides essential growth substances
- Sodium citrate holds certain inorganic cations in solution
- Glycerol provides carbon and energy
- Malachite green dye partially inhibits bacterial contaminants
Supplementation of the agar base is required in order to obtain mycobacterial growth. In the enriched medium, sodium chloride maintains osmotic equilibrium; oleic acid, as well as other long chain fatty acids, can be utilized by tubercle bacilli and plays an important role in the metabolism of mycobacteria; the primary effect of albumin is that of protection of the tubercle bacilli against toxic agents and, therefore, it enhances their recovery on primary isolation; dextrose is an energy source; and catalase destroys toxic peroxides that may be present in the medium.