Canavanine Glycine Bromothymol Blue (CGB) Agar.
For differentiation of C. neoformans and C. gattii (Kwon-Chung et al. 1982).
Solution A
Glycine Univar 10 g
KH2PO4 1 g
MgSO4 1 g
Thiamine HCl 1 mg
L-canavanine sulphate 30 mg
Distilled water 100 mL
Dissolve ingredients in small beaker and adjust pH to 5.6
Filter sterilise solution using 0.22 μm filter.
Store in refrigerator.
Solution B (aqueous bromothymol blue)
Bromothymol Blue 0.4 g
0.01N NaOH 64 mL
Distilled water 36 mL
Dissolve the Bromothymol Blue in the NaOH
Add to the water.
To prepare medium (1 litre for plates)
Distilled water 880 mL
Solution B 20 mL
Bacto agar (BD 214010) 20 g
Autoclave to 121C for 15 minutes, cool to 48C.
For plates add 100 mL of the filtered solution A and mix. Dispense as plates.