Liofilchem Gram Staining Kit, 4 X 250mL

The Liofilchem® Gram Staining Kit is a comprehensive solution for performing Gram staining, enabling microbiologists to differentiate between Gram-positive and Gram-negative microorganisms. This differentiation is vital for the taxonomic classification of prokaryotes and serves as a preliminary identification method in clinical and research microbiology.

Key Features

1. Comprehensive Kit Components:
   • Crystal Violet Solution (250 mL): Primary stain for Gram-positive bacteria.
   • Lugol-PVP Solution (250 mL): Acts as a mordant, forming a complex with Crystal Violet.
   • Decolourant Solution (250 mL): Removes Crystal Violet from Gram-negative bacteria.
   • Safranine Solution (250 mL): Counterstains Gram-negative bacteria.
2. Packaging:
   • Four 250 mL bottles, each securely sealed and equipped with a dropper lid for precise application.
   • Delivered in sturdy packaging to ensure safe transportation and storage.
3. Shelf Life:
   • Valid for up to 2 years when stored at recommended conditions (10–25°C).
4. Storage Conditions:
   • Protect from heat and temperature fluctuations.
   • Discard if the solutions show signs of deterioration, such as color changes or precipitates.
5. Ease of Use:
   • Ready-to-use solutions for convenience and accuracy.
   • Designed for professional laboratory environments.

Applications

1. Microbiological Diagnostics:
   • Differentiation between Gram-positive and Gram-negative bacteria based on cell wall properties.
   • Supports preliminary bacterial classification for clinical samples.
2. Clinical and Research Settings:
   • Essential for identifying pathogens in clinical samples such as blood, urine, and swabs.
   • Utilized in microbiology research for studying bacterial morphology.
3. Educational Laboratories:
   • Widely employed in teaching environments for training students in microbiological techniques.

Principle of Gram Staining

1. Mechanism:
   • Crystal Violet combines with iodine (from Lugol-PVP Solution) to form a complex that binds to bacterial cell walls.
   • Gram-positive bacteria retain the violet stain due to their thick peptidoglycan layer.
   • Gram-negative bacteria lose the Crystal Violet during the decolorization step due to their lipid-rich outer membrane, allowing Safranine to counterstain them red.
2. Differentiation:
   • Gram-positive bacteria: Appear blue/purple under the microscope.
   • Gram-negative bacteria: Appear red/pink under the microscope.

Procedure

1. Sample Preparation:
   • Use clean slides to prepare a smear of the sample or culture.
   • Air-dry and fix by passing the slide over a flame briefly.
2. Staining Process:
   • Cover the smear with Crystal Violet Solution for 1 minute; rinse gently with water.
   • Apply Lugol-PVP Solution for 1 minute; rinse gently with water.
   • Decolorize with the Decolourant Solution for 30–60 seconds until no color is released; rinse with water.
   • Apply Safranine Solution for 30–60 seconds; rinse with water.
   • Air-dry the slide.
3. Microscopic Observation:
   • Examine the stained slide using an immersion oil objective under a microscope.

Advantages

1. Reliable Results:
   • High-quality reagents ensure consistent and reproducible staining.
2. Convenient Packaging:
   • Four 250 mL bottles provide ample reagent for multiple tests.
3. Validated by Quality Control:
   • Tested with Escherichia coli ATCC 25922 (Gram-negative, red) and Staphylococcus aureus ATCC 25923 (Gram-positive, blue).
4. Educational and Diagnostic Value:
   • Useful for bacterial classification in both teaching and clinical contexts.

Precautions

1. Safety:
   • Contains substances classified as hazardous; consult the safety data sheet (SDS) before use.
   • Wear appropriate personal protective equipment (PPE), including gloves and lab coats.
2. Storage:
   • Ensure storage conditions are maintained to preserve reagent quality.
3. Waste Disposal:
   • Dispose of used reagents and materials following local regulations for biological and chemical waste.

Limitations

1. Preliminary Identification:
   • Gram staining provides initial identification and must be supplemented with culture and biochemical tests.
2. Sample Age:
   • Bacteria from older cultures may show altered staining results.
3. Antibiotic Effects:
   • Antibiotic-treated bacteria may decolorize more easily, appearing pinkish-red instead of blue.

Quality Control

• Positive Control:
  • Staphylococcus aureus ATCC 25923 (Gram-positive, blue).
• Negative Control:
  • Escherichia coli ATCC 25922 (Gram-negative, red).

Technical Specifications

Comparison Table: Gram Staining Kits by Liofilchem®, BD, Sigma-Aldrich, and Remel™

The Liofilchem® Gram Staining Kit (4 x 250 mL) is an essential tool for microbiologists, enabling reliable Gram staining for bacterial differentiation. Its high-quality reagents, ease of use, and consistent results make it a preferred choice for clinical diagnostics, research, and teaching applications.