Liofilchem® Safranin Solution, 1L

Liofilchem® Safranin Solution is a specialized staining reagent used in Gram staining procedures. It provides the critical counterstain step that differentiates Gram-negative bacteria (red-stained) from Gram-positive bacteria (blue-stained). The solution is formulated for consistent and high-quality results in clinical, research, and educational applications.

Key Features

• Purpose: Used as the counterstain in Gram staining to differentiate Gram-negative and Gram-positive bacteria.
• Formulation:
  • Safranin Concentration: 0.25%
  • Ethyl Alcohol: 20%
• Appearance: Clear red solution.
• Packaging Options:
  • 1L Bottle (Code: 80290)

Principle

Gram staining relies on the ability of Crystal Violet to form a complex with iodine, which is retained by Gram-positive bacteria after decolorization. In contrast, Gram-negative bacteria lose the Crystal Violet stain during decolorization and are counterstained with Safranin, giving them a red appearance.

Procedure

Preparation and Fixation:

1. Prepare Slide:
   • Streak the sample or culture on a clean slide.
   • Air-dry the slide and fix the sample by quickly passing it through a flame or using an alternative fixation method.
2. Staining:
   • Step 1: Cover the slide with Crystal Violet Solution for 1 minute, then rinse with water.
   • Step 2: Apply Lugol-PVP Solution for 1 minute, then rinse with water.
   • Step 3: Decolorize with Decoloring Solution until no further color is released (30-60 seconds), then rinse with water.
   • Step 4: Counterstain with Safranin Solution for 30-60 seconds, then rinse with water.
   • Step 5: Dry and observe under a microscope with an immersion objective.

Interpretation of Results

• Gram-negative bacteria: Appear red-stained after counterstaining with Safranin.
• Gram-positive bacteria: Retain the blue stain from Crystal Violet.
• Differentiation aids in:
  • Identifying Gram-negative bacilli versus Gram-positive bacilli.
  • Identifying Gram-negative cocci versus Gram-positive cocci.

Storage

• Store at 10–25°C away from light.
• Ensure proper sealing to avoid contamination or deterioration.
• Shelf life: 2 years.

Quality Control

Each batch is subjected to rigorous quality control to ensure reliable staining:

• Gram-negative control: Escherichia coli ATCC 25922 (red-stained).
• Gram-positive control: Staphylococcus aureus ATCC 25923 (blue-stained).

Precautions

• Contains potentially hazardous substances—refer to the Safety Data Sheet (SDS).
• For in vitro diagnostic use only.
• Must be handled by trained laboratory personnel using aseptic and safety procedures.

Applications

• Clinical Microbiology: Rapid identification and differentiation of Gram-positive and Gram-negative bacteria in patient samples.
• Research Microbiology: Fundamental staining method for bacterial taxonomy and morphology studies.
• Educational Use: Demonstrates basic microbiological staining techniques in academic settings.

Packaging Information

References

1. Kruczak-Filipov, P., and R.G. Shively. 1992. Clinical Microbiology Procedures Handbook. ASM, Washington, D.C.
2. Murray, P.R. (ed.) 1999. Manual of Clinical Microbiology, 7th ed. ASM, Washington, D.C.