Columbia Blood Agar Base

Columbia Blood Agar Base
Enriched Blood Agar Base for Fastidious and Non-Fastidious Bacteria

Catalog Number: AS-1180

Overview
Columbia Blood Agar Base, when supplemented with 5–10% defibrinated sheep blood, produces Columbia Blood Agar—a highly enriched, non-selective solid medium for the primary isolation, cultivation, and characterisation of fastidious and non-fastidious microorganisms from clinical specimens such as blood, throat swabs, wounds, and genital samples.

Formulated with specialised Columbia peptone (a refined meat digest) and enriched with yeast and beef extracts, the medium supports superior growth and colony development. Blood supplementation enables clear visualisation of haemolytic reactions (alpha, beta, gamma), critical for presumptive identification of streptococci, staphylococci, and other clinically relevant organisms. Corn starch neutralises toxic metabolites, improving recovery of stressed or low-viability cells.

Applications
• Isolation of beta-haemolytic streptococci such as Streptococcus pyogenes and S. agalactiae from throat and respiratory specimens
• Cultivation of Haemophilus influenzae, Neisseria meningitidis, and viridans streptococci from blood, CSF, and respiratory samples
• Observation of haemolysis patterns for presumptive identification in antimicrobial susceptibility workflows
• General-purpose enriched medium for mixed flora in wound, urine, and food microbiology testing

Key Features & Benefits
• Columbia peptone enhances colony size, morphology, and pigment production
• Blood supplementation provides X-factor (hemin) and enables clear haemolysis
• Corn starch buffers toxic by-products and stabilises growth conditions
• Produces well-defined haemolytic zones without distortion from overgrowth
• Suitable for aerobic and CO₂-enriched incubation environments

Principle of the Medium
Columbia Blood Agar Base supplies a rich nutrient environment through refined meat digests and yeast extract, promoting robust bacterial growth. Addition of defibrinated sheep blood provides essential growth factors and allows differentiation of organisms based on haemolytic activity. Corn starch absorbs inhibitory substances, enhancing recovery of fastidious organisms and improving colony clarity.

Typical Composition (per litre)
Pancreatic Digest of Casein – 12.0 g
Peptic Digest of Animal Tissue – 5.0 g
Yeast Extract – 3.0 g
Beef Extract – 3.0 g
Corn Starch – 1.0 g
Sodium Chloride – 5.0 g
Agar – 13.5 g

Supplement (added after sterilisation):
Defibrinated Sheep Blood – 50–100 mL (5–10%)

Final pH: 7.3 ± 0.2 at 25 °C

Preparation
Suspend 39.5 g of dehydrated base in 950 mL purified or distilled water.
Heat with gentle agitation to boiling until completely dissolved; do not overheat.
Sterilise by autoclaving at 121 °C (15 psi) for 15 minutes.
Cool to 45–50 °C in a water bath.
Aseptically add 50–100 mL sterile defibrinated sheep blood and mix gently to avoid haemolysis.
Pour into sterile Petri dishes (20–25 mL per plate) or dispense as required.
Allow to solidify and dry briefly under aseptic conditions.

The prepared medium should appear opaque, reddish-brown, and homogeneous without bubbles or separation.

Incubation
Inoculate using a calibrated loop or sterile swab.
Incubate at 35–37 °C aerobically or in 5% CO₂.
Typical incubation time: 18–48 hours.

Storage & Stability
Dehydrated medium: Store at 10–30 °C in a tightly closed container, protected from moisture and light
Prepared plates: Store at 2–8 °C in sealed plastic bags and use within 4–8 weeks
Discard plates that are dehydrated, haemolysed, discoloured, contaminated, or overgrown

Intended Use
For laboratory research and microbiological quality control use only.
Not for human or veterinary consumption.
Not for diagnostic use without appropriate validation.

Quality & Compliance
Manufactured under controlled conditions to ensure batch-to-batch consistency.
Suitable for clinical, food, and environmental microbiology laboratories.
Performance comparable to leading international blood agar formulations.

Customs & Trade Information
HS / AHECC Code: 3821.00.00
Prepared culture media for the development or maintenance of microorganisms