McKinney:7H9

Summary
7H9 (and its solid counterpart, 7H10 agar) are selective media used for the culture of free-living mycobacteria such as M. tuberculosis and M. smegmatis.

Ingredients
(makes 1L medium)


 * Deionized water
 * 4.7g Middlebrook 7H9 powder (DifCo catalog # 0713-01-7)
 * 5mL 10% Tween-80: Dilute 40g Tween-80 (liquid) into final volume 200mL with deionized water. Stir on low heat (~65&deg;C) until completely dissolved (may take ~15 minutes).  Filter sterilize with a 0.22&mu;m filter.  Store at 4&deg;C wrapped in aluminum foil, as Tween is light sensitive.

For M. tuberculosis:
 * 100mL OADC (Dubos/Middlebrook Oleic Acid Albumin Dextrose Complex)
 * 10mL 50% glycerol
 * (If you are using lung homogenates or the like) 10mL 10mg/mL cyclohexamide

For M. smegmatis:
 * 100mL ADS (Albumin-Dextrose-Saline): 8.1g NaCl, 50g Bovine Serum Albumin Fraction V, 20g anhydrous dextrose in 1L deionized water.  Filter sterilize in a 0.22&mu;m filter, and store at 4&deg;C.

Protocol

 * 1) Dissolve 4.7g Middlebrook 7H9 poweder in 900mL deionized water.  Mix with a magnetic stir bar until soluble components have dissolved.
 * 2) Add the rest of the ingredients appropriate for the organism at hand and continue stirring until well mixed.
 * 3) Sterilize by filtration through a 0.22&mu;m pore membrane.  Store at 4&deg;C.