Gram Staining Protocol: Standard Microbiology Sop

STANDARD OPERATING PROCEDURE (SOP)

Document ID: SOP-MB-001
Title: Gram Staining Protocol
Effective Date: [___________]
Revision Number: [___________]

1. PURPOSE

The purpose of this Standard Operating Procedure (SOP) is to provide a standardized, reproducible methodology for the Gram staining of microbiological specimens to determine the morphology and cell wall characteristics of bacterial populations.

2. SCOPE

This procedure applies to all personnel within the [___________] Department/Laboratory who are authorized to perform microscopic examinations of bacterial cultures.

3. RESPONSIBILITIES

• Laboratory Manager: Responsible for ensuring the availability of calibrated equipment and certified reagents.
• Authorized Personnel: Responsible for adherence to the protocol and documentation of results.
• Quality Assurance (QA) Officer: Responsible for periodic review of staining records and equipment maintenance logs.

4. MATERIALS AND REAGENTS

Ensure all reagents are within their expiration dates:

• Primary Stain: Crystal Violet
• Mordant: Gram’s Iodine
• Decolorizer: [___________] (e.g., 95% Ethanol or Acetone-Alcohol)
• Counterstain: Safranin
• Distilled Water (dH₂O)
• Microscope slides, inoculation loops, and Bunsen burner/incinerator.

5. PROCEDURE

5.1 Preparation of Smear

1. Place a small drop of sterile water/saline on a clean microscope slide.
2. Aseptically transfer a small amount of the specimen [___________] (Sample ID/Source) to the slide.
3. Allow the smear to air-dry completely.
4. Heat-fix the slide by passing it through the flame [___________] times.

5.2 Staining Protocol

1. Crystal Violet: Apply for [___________] seconds. Rinse with dH₂O.
2. Gram’s Iodine: Apply for [___________] seconds. Rinse with dH₂O.
3. Decolorizer: Apply dropwise until runoff is clear (approx. [___________] seconds). Rinse immediately with dH₂O.
4. Safranin: Apply for [___________] seconds. Rinse with dH₂O.
5. Blotting: Gently blot dry using bibulous paper.

6. OBSERVATION AND RESULTS

• Microscopy: Observe under 100x oil immersion objective.
• Gram-Positive Bacteria: Appear [___________] (Color).
• Gram-Negative Bacteria: Appear [___________] (Color).
• Notes: [________________________________________________________________]

7. QUALITY CONTROL

• Positive Control Organism: [___________]
• Negative Control Organism: [___________]
• Lot Number of Reagents: [___________]

8. AUTHORIZATION AND SIGNATURES

By signing below, the undersigned acknowledges that they have read, understood, and will comply with the procedures outlined in this SOP.

Prepared By:
Name: [___________________________]
Title: [___________________________]
Date: [___________]
Signature: ___________________________

Reviewed By (Quality Assurance):
Name: [___________________________]
Title: [___________________________]
Date: [___________]
Signature: ___________________________

Approved By (Laboratory Director):
Name: [___________________________]
Title: [___________________________]
Date: [___________]
Signature: ___________________________