Thermo Scientific™ Oxoid™ Tryptone Water (Dehydrated)

Thermo Scientific™ Oxoid™ Tryptone Water is a liquid medium designed for the production and detection of indole by microorganisms. Its high content of tryptophan makes it a reliable substrate for performing indole tests, widely used in the classification and identification of bacteria.

Key Features:

1. Reliable Substrate:
   • High tryptophan content ensures accurate results in indole production tests, outperforming Peptone Water for this application.
2. Wide Application:
   • Used for the classification and identification of microorganisms capable of indole production.
   • Detects Escherichia coli specifically at 44°C, facilitating its identification in water testing.
3. Standardized Methodology:
   • Compatible with Kovac's reagent and Ehrlich reagent for indole detection.
4. Quality-Controlled Formula:
   • Supports growth and consistent indole production in standard bacterial strains.

Typical Formula (per liter):

Preparation Instructions:

1. Reconstitution:
   • Dissolve 15 g of Tryptone Water powder in 1 liter of distilled water.
2. Sterilization:
   • Autoclave at 121°C for 15 minutes.
3. Dispensing:
   • Distribute into final containers before autoclaving.

Indole Detection Technique:

Using Kovac's Reagent:

1. Preparation of Reagent:
   • 5 g paradimethylaminobenzaldehyde, 75 mL amyl alcohol, 25 mL concentrated HCl.
2. Procedure:
   • Inoculate Tryptone Water tubes with test organism and incubate at 35°C for 24–48 hours.
   • Add 0.2 mL Kovac's reagent, shake, and let stand for 10 minutes.
   • A dark red layer indicates a positive indole reaction.

Using Ehrlich Reagent:

1. Preparation of Reagent:
   • 4 g paradimethylaminobenzaldehyde, 380 mL absolute alcohol, 80 mL concentrated HCl.
2. Procedure:
   • Inoculate and incubate as above.
   • Add an equal volume of reagent to the culture; a rose color indicates indole presence.
   • Alternatively, extract indole using ether and test with Ehrlich reagent.

Applications:

1. Water and Wastewater Testing:
   • Indole production at 44°C serves as a specific test for Escherichia coli.
2. Microbial Identification:
   • Differentiates bacteria based on their ability to degrade tryptophan into indole.
3. Clinical and Food Microbiology:
   • Assists in identifying enteric bacteria in various samples.

Quality Control:

Storage and Shelf Life:

• Dehydrated Medium: Store at 10–30°C in a dry environment.
• Prepared Medium: Store at room temperature, away from light.

Advantages:

Precautions:

• Perform sterility tests in strict aseptic conditions.
• Ensure proper disposal of waste according to local regulations.

References:

1. American Public Health Association (1998). Standard Methods for the Examination of Water and Wastewater. 20th Edition, APHA Inc., Washington DC.
2. Farmer J.J. III et al. (1985). Journal of Clinical Microbiology. 21: 46-76.
3. DHSS (1982). The Bacteriological Examination of Drinking Water Supplies. HMSO, London.

Thermo Scientific™ Oxoid™ Tryptone Water offers a reliable solution for the detection of indole production, supporting microbiological identification in clinical, food, and water testing laboratories.