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ANAEROBE IDENTIFICATION AGAR BASE

A medium for testing the fermentation capabilities of non-sporing anaerobes.

Code: CB1/1566

Typical formula  g/l

Beef extract

4.0

Peptone mixture 16.0
Sodium chloride 5.0
Agar 15.0

pH: 7.2 ± 0.2

Directions

Weigh 40 g of powder, disperse in 1 litre of deionised water. Allow to stand for 10 minutes, swirl to mix then sterilise by autoclaving at 121șC for 15 minutes. Cool to 48șC and aseptically add 50-70mls of sterile defibrinated horse blood. Mix well and pour. Before use, flood the surface with 1 ml of a sterile solution of the substrate under test.

Q.C. organisms:

B. fragilis

Storage: Plates up to 7 days at 2-8șC in the dark. Capped Container up to 3 months at 15-20șC in the dark.

Inoculation: Heavily inoculate a small area of the plate with a loopful of a fresh culture of the test organism. Up to 4 organisms per plate can be tested.

Incubation: 37șC anaerobically for 24-48 hours.

Recognition of fermentation: Remove a small plug of agar from below the growth. Cover the plug with bromothymol blue indicator (0.04%). Colour changes due to production of acidity will develop in a few seconds and should be viewed against a white background. Comparison with controls is useful; a plug taken from an area well away from any growth can be used as a negative control.

References

Phillips K.D. 1976. A Simple and sensitive technique for determining the fermentation reactions of non-sporing anaerobes. J. Appl. Bact. 41: 325-328.

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