Bacillus cereus Selective Agar Base

[所属分类:培养基配方] [发布时间:2019-11-27] [发布人:] [阅读次数:] [返回]

山东拓普生物工程有限公司

Shandong Tuopu Biol-Engineering Co.,Ltd

Bacillus cereus Selective Agar Base
Composition per liter:
Agar.........................................................................15.0g
Sodium pyruvate..............................................................10.0g
Mannitol.....................................................................10.0g
Na2HPO4 ......................................................................2.5g
NaCl..........................................................................2.0g
Peptone ......................................................................1.0g
KH2PO4 ......................................................................0.25g
Bromthymol Blue..............................................................0.12g
MgSO4 ·7H2O..................................................................0.1g
Egg yolk emulsion...........................................................25.0mL
Polymyxin B solution........................................................10.0mL
pH 7.2 ± 0.2 at 25°C
Source:  This medium is available as a premixed powder from Oxoid
Unipath.
Egg Yolk Emulsion:
Composition :
Chicken egg yolks..................................................................... 11
Whole chicken egg .....................................................................1
Preparation of Egg Yolk Emulsion: Soak eggs with 1:100 dilu-
tion of saturated mercuric chloride solution for 1 min. Crack eggs and
separate yolks from whites. Mix egg yolks with 1 chicken egg.
Polymyxin B Solution:
Composition per 10.0mL:
Polymyxin B........................................................................ 100,000U
Preparation of Polymyxin B Solution: Add polymyxin B to dis-
tilled/deionized water and bring volume to 10.0mL. Mix thoroughly.
Filter sterilize.
Preparation of Medium:  Add components, except egg yolk emul-
sion and polymyxin B solution, to distilled/deionized water and bring
volume to 965.0mL. Gently heat and bring to boiling. Distribute into
tubes or flasks. Autoclave for 15 min at 15 psi pressure–121°C. Cool
to 50°C. Aseptically add sterile polymyxin B and 25.0mL of sterile egg
yolk emulsion. Mix thoroughly. Pour into sterile Petri dishes or leave
in tubes.
Use: For the selection and presumptive identification of Bacillus
cereus. Also for the isolation and enumeration of these bacteria. Bacil-
lus cereus grows as moderate-sized (5mm) crenated colonies, which
are turquoise, surrounded by a precipitate of egg yolk, which is also
turquoise.