OXOID TCBS Agar – Selective Medium for Vibrio (Cholera) Detection

 Overview

OXOID TCBS Agar (Thiosulfate Citrate Bile Salts Sucrose Agar) is a highly selective and differential culture medium used for the isolation of Vibrio species, especially Vibrio cholerae and Vibrio parahaemolyticus. It is widely used in clinical, food, and environmental microbiology laboratories for the detection of cholera-causing organisms.

Manufactured by Oxoid Ltd., part of Thermo Fisher Scientific, TCBS Agar ensures high sensitivity, selectivity, and consistent laboratory performance.

 Principle of TCBS Agar

TCBS Agar is designed to selectively isolate Vibrio species while differentiating them based on sucrose fermentation:

• High pH (alkaline medium) inhibits most non-Vibrio organisms
• Bile salts and citrate suppress Gram-positive bacteria and many enterics
• Sucrose differentiates fermenting and non-fermenting Vibrio
• Bromothymol blue & thymol blue act as pH indicators
• Sodium thiosulfate supports sulfur metabolism

Colony Appearance:

• Vibrio cholerae → Yellow colonies (sucrose fermenter)
• Vibrio parahaemolyticus → Green/blue-green colonies (non-sucrose fermenter)
• Other bacteria → Inhibited or minimal growth

 Key Features & Benefits

• Highly selective for Vibrio species
• Differential identification based on sucrose fermentation
• Clear colony color differentiation
• Reliable for rapid screening of cholera pathogens
• Consistent, high-quality formulation

 Applications

• Clinical diagnosis of cholera and Vibrio infections
• Food microbiology (seafood testing)
• Water quality testing and environmental monitoring
• Public health laboratories
• Research and academic studies

 Composition (Typical per Liter)

• Peptone & Yeast extract – Nutrient sources
• Sodium thiosulfate – Sulfur source
• Sodium citrate & bile salts – Selective agents
• Sucrose – Fermentable carbohydrate
• Bromothymol blue & thymol blue – pH indicators
• Agar – Solidifying agent

 Preparation & Usage Instructions

Important: Do NOT autoclave TCBS Agar (heat-sensitive components)

1. Suspend the medium in distilled water
2. Heat gently with stirring to dissolve completely
3. Do not overheat or autoclave
4. Cool to about 45–50°C
5. Pour into sterile Petri dishes
6. Allow to solidify
7. Inoculate sample and incubate at 35–37°C for 18–24 hours

 Storage & Shelf Life

• Store at 10–30°C in a dry place
• Keep tightly closed
• Protect from moisture and direct sunlight

 Why Choose OXOID TCBS Agar?

• Globally trusted microbiology brand
• High selectivity for Vibrio species
• Accurate and easy-to-interpret results
• Ideal for outbreak investigation and routine testing