3% NaCl TSI Agar – 250g | Vibrio parahaemolyticus Biochemical Test Medium
3% NaCl Triple Sugar Iron (TSI) Agar is a specialized biochemical test medium for differentiating Vibrio parahaemolyticus from other enteric bacteria, featuring high salinity (3% NaCl) to support halophilic growth while assessing carbohydrate utilization and hydrogen sulfide production.
Key Applications:
✔️ Biochemical confirmation of V. parahaemolyticus post-TCBS isolation
✔️ Differentiation from V. vulnificus and V. alginolyticus
✔️ Sugar fermentation profiling: Glucose/Lactose/Sucrose
✔️ H₂S production detection per FDA BAM Chapter 9
Differential Formula (Per Liter):
| Component | Quantity | Function |
|————————-|———-|———-|
| Sugars | | |
| Lactose | 10.0 g | Fermentation substrate |
| Sucrose | 10.0 g | Fermentation substrate |
| Dextrose | 1.0 g | Fermentation substrate |
| Indicators | | |
| Ferrous Sulfate | 0.2 g | H₂S detection |
| Sodium Thiosulfate | 0.3 g | H₂S source |
| Phenol Red | 0.024 g | pH indicator |
| Salt Base | | |
| Sodium Chloride | 30.0 g | Halophilic support |
Final pH: 7.4 ± 0.2 (25°C)
Protocol Essentials:
1️⃣ Suspend 89.5g powder in 1L distilled water
2️⃣ Boil ≥1 minute with continuous stirring
3️⃣ Dispense into tubes (5ml deep butt + slanted surface)
4️⃣ Autoclave at 121°C for 15 minutes
Interpretation Guide for Vibrios:
| Reaction | Slant Color | Butt Color | H₂S | Interpretation |
|——————-|————-|————|—–|—————|
| V. parahaemolyticus | Red | Yellow | – | Glucose+ only |
| V. vulnificus | Yellow | Yellow | + | Lactose/Sucrose+ |
