No.4 Agar Base – 250g | Selective Medium for Vibrio cholerae Isolation

No.4 Agar Base is a highly selective medium optimized for primary isolation of Vibrio cholerae from stool samples, environmental waters, and outbreak investigations, featuring multiple inhibitory agents to suppress competing flora.

Critical Applications:

✔️ Isolation of V. cholerae in cholera surveillance

✔️ Clinical diagnosis of suspected cholera cases

✔️ Environmental monitoring in endemic regions

✔️ Food and water safety testing

Selective Formula Components (Per Liter):

– Peptone: 20.0g

– Beef Extract: 5.0g

– Sodium Sulfite: 3.0g

– Sodium Chloride: 5.0g

– Sodium Dodecyl Sulfonate: 0.5g

– Bile Powder: 5.0g

– Ethacridine Lactate: 0.03g

– Gentamycin: 500U

– Agar: 15.0g

Final pH: 8.5 ± 0.2 (25°C)

Essential Protocol:

1️⃣ Suspend 53.5g in 1L distilled water

2️⃣ Boil 1-2 minutes with continuous stirring

3️⃣ Cool to 50-55°C

4️⃣ Add 1 vial Potassium Tellurite (2mg) per 200ml

5️⃣ Mix → Pour plates

Technical Advantages:

– Multi-agent inhibition: Bile salts + antibiotics + surfactants

– Alkaline selectivity: pH 8.5 suppresses non-vibrio species

– Tellurite enhancement: Improves V. cholerae colony morphology

– Ready-to-use powder: Consistent performance

– 3-year stability: Foil-sealed packaging

Operational Note:

– Potassium Tellurite is added post-sterilization

– Store tellurite vials refrigerated