Bird Seed Agar

For the selective isolation of Cryptococcus neoformans and C. gattii.

Ingredients

Guizotia abyssinica (niger seed) 50 g

Glucose 1 g

KH₂PO₄ (potassium dihydrogen orthophosphate) 1 g

Creatinine 1 g

Bacto-agar (BD) 15 g

Distilled water 1000 mL

Additives: to each 500 ml bottle.

Penicillin G (20 units/ml) 1 mL

Gentamicin (40 mg/ml) 1 mL

Method

Grind seeds of Guizotia abyssinica as finely as possible with an electric grinder and add to 1000 ml distilled water in a stainless steel jug.

Boil for 30 minutes, pass through filter paper and adjust volume to 1000 mL.

Add remaining ingredients except Bacto-agar to filtrate and dissolve.

If required: Cool to room temperature and pH to 5.5

Dispense into 500 mL bottles.

Add 7.5 g Bacto-agar to each 500 mL reagent bottle.

Autoclave at 121C for 20 minutes.

Cool to 48C and add 0.5 ml Penicillin G and 0.5 ml Gentamicin to each 500 ml of Bird Seed Agar.

Mix gently and pour into 90 mm plastic petri dishes.