Liofilchem™ Indole Test, 30 Tests

The Liofilchem™ Indole Test is a rapid diagnostic kit designed to detect indole production in bacterial isolates. The test is used to qualitatively determine indole production as a key step in identifying certain non-lactose fermenting organisms and differentiating bacterial species such as Escherichia coli and Proteus mirabilis.

Key Features

1. Rapid and Accurate Detection:
   • Provides results within 30 seconds after the addition of Kovac’s Reagent.
2. Comprehensive Kit:
   • Includes pre-measured test tubes and Kovac’s reagent for convenience.
3. Validated for Clinical Use:
   • Tested with standard control strains to ensure reliable results.
4. Simple Colorimetric Interpretation:
   • Positive reaction: Red ring.
   • Negative reaction: Yellow or brown ring.

Kit Contents

• 30 Indole Test tubes (desiccated biochemical substrates).
• 1 vial of Kovac’s Reagent (3 mL).

Method Principle

• Indole Production:
  • Bacteria producing the enzyme tryptophanase degrade tryptophan into indole, pyruvic acid, and ammonia.
  • Kovac’s Reagent reacts with indole to form a red-violet compound, indicating a positive result.

Applications

1. Clinical Microbiology:
   • Differentiates E. coli (positive) from Salmonella and Proteus mirabilis (negative).
2. Food and Environmental Testing:
   • Identifies indole-producing organisms in samples.
3. Research:
   • Studies on bacterial metabolism and identification.

Test Procedure

1. Take the required number of Indole Test tubes and allow them to reach room temperature.
2. Add 0.3 mL of physiological saline to each tube.
3. Inoculate heavily with the test organism (from a fresh overnight culture).
4. Incubate at 35 ± 2°C for up to 24 hours.
5. Add 2-3 drops of Kovac’s Reagent and observe for color change within 30 seconds.

Interpreting Results

Quality Control

• Expected Reactions:

  Control Strain	Reaction
  Escherichia coli ATCC® 25922	Positive (Red ring)
  Proteus mirabilis ATCC® 29906	Negative (Yellow)
  Salmonella Typhimurium ATCC® 14028	Negative (Yellow)

• Appearance:
  • Indole Test: Yellowish powder, clear yellow solution upon reconstitution.
  • Kovac’s Reagent: Clear yellow-green liquid.

Storage and Shelf Life

• Storage:
  • Store at 2–8°C in original packaging, away from heat and direct sunlight.
• Shelf Life:
  • Valid for 1 year when stored as recommended.

Advantages

• Rapid Results:
  • Provides results in seconds after reagent addition.
• Validated Performance:
  • Ensures accuracy with tested control strains.
• Convenient:
  • Pre-measured components simplify testing procedures.
• Cost-Effective:
  • Provides 30 tests per kit, suitable for medium-throughput labs.

Warnings and Precautions

1. For in vitro diagnostic use (IVD) only.
2. Handle all microbiological specimens and reagents as potentially infectious.
3. Use pure cultures for accurate results.
4. Dispose of waste materials according to local regulations.

Limitations

• Prolonged incubation may result in false positives due to protein hydrolysis.
• Pigmented organisms may yield ambiguous results.
• Some anaerobes rapidly degrade indole, leading to potential false negatives.

Packaging

References

1. EN ISO 11133:2014+Amd1:2018+Amd2:2020. Microbiology of food, animal feed and water.
2. Public Health England (2018). Indole Test, UK Standards for Microbiology Investigations.
3. MacFaddin J.F. (1980). Biochemical tests for identification for medical bacteria.
4. Blazevic D.J., Ederer G.M. (1975). Principles of biochemical tests in diagnostic microbiology.

Why Choose Liofilchem Indole Test?

• Proven Accuracy: Trusted for rapid and reliable differentiation of bacterial isolates.
• Easy to Use: Pre-measured tubes and reagents simplify workflows.
• Validated Results: Ensures consistency with quality control strains.