Bird Seed Agar

For the selective isolation of Cryptococcus neoformans.

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) 0.5 ml

Gentamicin (40 mg/ml) 0.5 ml

Method:

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

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

3. Add remaining ingredients except Bacto-Agar to filtrate and dissolve.

4. If required: Cool to room temperature and pH to 5.5

5. Dispense into 500 ml bottles.

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

7. Autoclave at 110C for 20 minutes.

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

9. Mix gently and pour into 90 mm plastic petri dishes.