Sodium bicarbonate

0.4

Ferric pyrophosphate

0.5

Haemin

0.005

Vitamin K

0.0005

Dithiothreitol

0.25

Agar

12.0

pH 6.8 ± 0.2 @ 25°C

Directions
Suspend 46g in 1 litre of distilled water. Sterilise by autoclaving at 121°C for 15 minutes. Cool to 50-55°C and aseptically add 5-10% sterile Defibrinated Horse Blood SR0050.

Mix well and pour into sterile Petri dishes.

Description
Anaerobe Basal Agar contains peptones, carefully selected to support good growth of anaerobic bacteria and yeast extract as a vitamin source. Starch is present to absorb any toxic metabolites¹. Sufficient arginine is added to ensure the growth of Eubacterium lentum², whilst haemin and vitamin K are growth factors required by many Bacteroides species³. Haemin is also required by Porphyromonas species. Sodium succinate improves the growth of Prevotella melaninogenica and Bacteroides species⁴. Sodium pyruvate is added 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 media components⁵. L-cysteine hydrochloride and dithiothreitol are reducing agents, and cysteine has also been shown to stimulate the growth of some anaerobes⁶.

Technique
Inoculate the medium by surface plating to obtain single colonies. Incubate anaerobically for up to 5 days at 37°C. Anaerobic conditions can be achieved using the Oxoid AnaeroGen Atmosphere Generation System AN0025 with the Oxoid AnaeroJar AG0025.

The medium may be rendered selective for Gram-negative anaerobes by the addition of G-N supplement SR0108 and for non-sporing anaerobes by the addition of N-S supplement SR0107 with Tween 80. Neomycin Selective Supplement SR0163 can be added to select for Clostridia.

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 plates of medium for upto 3 weeks at 2-8°C.

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

Quality control