Liofilchem® Chromatic™ Detection

Liofilchem® Chromatic™ Detection is a chromogenic non-selective culture medium designed for the enumeration, isolation, and presumptive identification of microorganisms from a wide range of clinical and non-clinical samples.

The medium supports the growth of both Gram-positive and Gram-negative organisms, allowing differentiation based on colony color and morphology using chromogenic substrates. It is particularly useful for routine microbial screening, surface testing, and sample purity assessments in clinical, industrial, pharmaceutical, and environmental laboratories.

In addition, Chromatic™ Detection enables performance of the indole test for confirmation of Escherichia coli, providing an added diagnostic advantage for laboratories that require both quantitative and qualitative results.

Key Features

• Non-selective chromogenic agar for general microbial detection and differentiation.
• Supports a wide range of bacterial species, including E. coli, Klebsiella, Proteus, Staphylococcus, Pseudomonas, and Enterococcus.
• Distinct colony colors enable rapid presumptive identification.
• Compatible with both clinical and environmental testing workflows.
• Allows indole test confirmation of E. coli colonies directly on plate.
• Simple interpretation and high productivity ratio (≥70%).
• Available in dehydrated, bottled, and ready-to-use plate formats.
• Intended for in vitro diagnostic (IVD) use.

Typical Formula (per litre)

Principle of the Method

• Peptone and tryptone provide nitrogen, amino acids, and vitamins to promote bacterial growth.
• Yeast extract supplies additional B-group vitamins.
• Sodium chloride maintains osmotic balance.
• Chromogenic substrates enable differentiation based on species-specific enzyme activity, resulting in distinct colony colors.
• Agar solidifies the medium, allowing colony morphology analysis.

Preparation

Dehydrated Medium

1. Suspend 56.1 g of powder in 1 L of distilled or deionized water.
2. Heat to boiling for 1 minute, mixing frequently until fully dissolved.
3. Autoclave at 121°C for 15 minutes.

Medium in Bottles

1. Loosen the cap and melt in a water bath at 100°C until completely dissolved.
2. Tighten the cap and mix gently to ensure homogeneity.
3. Cool to 45–50°C, mix carefully (avoid foaming), and pour into Petri dishes aseptically.

Test Procedure

1. Ensure plates are dry and at room temperature before inoculation.
2. Inoculate by direct streaking, spread plating, or from enrichment culture for isolated colonies.
3. Incubate aerobically at 35 ± 2°C for 18–24 hours.
4. Examine colonies for characteristic colors and morphology.

Interpretation of Results

Note: Further biochemical or molecular tests are required to confirm presumptive identifications.

Quality Control

Incubation: 35 ± 2°C for 18–24 h (aerobic).

Appearance (Dehydrated Medium): beige, homogeneous, free-flowing powder.

Appearance (Prepared Medium): slightly opalescent, amber.

Storage and Stability

• Store dehydrated medium at 10–30°C in a dry, tightly sealed container.
• Store bottles and prepared plates at 2–8°C, protected from light.
• Shelf life:
  • Dehydrated medium – 2 years
  • Bottled medium – 1 year
  • Ready-to-use plates – 4 months

Safety and Handling

• For in vitro diagnostic use only.
• Handle samples using appropriate biosafety level 2 (BSL-2) precautions.
• Use by trained laboratory personnel only.
• Refer to the Safety Data Sheet (SDS) for safe handling information.
• Dispose of waste following national and institutional regulations.

Ordering Information

Liofilchem® Chromatic™ Detection provides a versatile, non-selective chromogenic medium for the enumeration and presumptive identification of a wide variety of microorganisms. It is an ideal solution for bacterial screening, hygiene monitoring, clinical diagnostics, and quality control, offering clear colony differentiation and compatibility with downstream identification methods such as biochemical or molecular testing.