Dehydrated Culture Media

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WILKINS-CHALGREN ANAEROBE BROTH

Code: CM0643

A medium for the general growth and antimicrobial susceptibility testing of anaerobic organisms. See Antimicrobial Susceptibility Testing Section 6 for details of the use of this medium in AST methodology.

Typical Formula*

gm/litre

Tryptone

10.0

Gelatin peptone

10.0

Yeast extract

5.0

Glucose

1.0

Sodium chloride

5.0

L-Arginine

1.0

Sodium pyruvate

1.0

Menadione

0.0005

Haemin

0.005

pH 7.1 ± 0.2 @ 25°C

 

* Adjusted as required to meet performance standards 

Directions
Suspend 33g in 1 litre of warm distilled water. Mix well, distribute into final containers and sterilise by autoclaving at 121°C for 15 minutes.

Description
Wilkins-Chalgren Anaerobe Broth is derived from Wilkins-Chalgren Anaerobe Agar1 CM0619.

Where studies on antimicrobial susceptibilities are being made both in broth and agar, standardisation is improved by using media of identical nutrient formulation.

The growth of anaerobic organisms in this broth is particularly good. The formulation includes yeast extract to supply vitamins and other growth factors such as purines and pyrimidines, that are necessary for good growth of Peptostreptococcus anaerobius and Bacteroides melaninogenicus. Arginine is added to ensure sufficient amino-acid is available for the growth of Eubacterium lentum. Pyruvate is present as an energy source for asaccharolytic cocci such as Veillonella. It also acts similarly to catalase and degrades traces of hydrogen peroxide, which may be produced by the action of molecular oxygen on medium constituents and interfere with the metabolism of anaerobes. Haemin is found to be essential for the growth of Bacteroides species and menadione for Bacteroides melaninogenicus.

Peptones derived from the single protein sources casein and gelatin are used to improve standardisation of the medium. The early heavy growth that is usual may reflect the absence of Eh-reducing substances that can be inhibitory to some organisms.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared medium at 2-8°C away from light.

Appearance
Dehydrated medium: Straw coloured, free-flowing powder
Prepared medium: Straw coloured solution

Quality control

Positive controls:

Expected results

Peptostreptococcus anaerobius ATCC® 27337*Turbid growth
Clostridium sporogenes ATCC®19404*

Turbid growth

Negative control:

 

Uninoculated medium

No change

* This organism is available as a Culti-Loop®

Reference
1. Wilkins T. D. and Chalgren S. (1976) Antimicrob. Agents Chemother. 10. 926-928.

 
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