VL Anaerobic Blood Agar

It contains peptone and ox extract, whose amino acids included in the medium work by reducing the pH. This reduction must be strong because the media for anaerobes must have a low potential for oxidation-reduction.

Peptones also provide nitrogen, vitamins, minerals and amino acids essential for growth.

L-cysteine and yeast extract are sources of nitrogen and carbon. The yeast extract is also a source of vitamin B. Glucose is the carbohydrate energy source. Sodium chloride supplies essential electrolytes for transport and osmotic balance. Bacteriological agar is the solidifying agent.

Preparation

Suspend 42 grams of the medium in 950 mL of distilled water. Mix well and dissolve by heating with frequent agitation. Boil for one minute until complete dissolution. Sterilize in autoclave at 121 °C for 15 minutes. Cool to 45-50 °C and aseptically add 50 mL of sterile defibrinated blood and 1 mL of 1% vitamin K1. Homogenize gently and pour into Petri dishes.

Instructions for use

Inoculate the sample on the plate and incubate at a temperature of 35 ± 2 °C for 24-48 hours.

• Dowell, V.R., Jr., G.L. Lombard, F.S. Thompson, and A.Y. Armfield. 1981. Media for Isolation, Characterization, and Identification of Obligately Anaerobic Bacteria. U.S. Dept. of H.H.S. and CDC, Atlanta, GA.
• Clinical and Laboratory Standards Institute (CLSI). 2004. Quality Control for Commercially Prepared Microbiological Culture Media; Approved Standard, 3rd ed. M22-A3. CLSI, Wayne, PA.