SGD On Gram Staining Step-by-Step Procedure: Theory, Mechanism, and Practical Tips | MBBS

Описание: This video is essential for MBBS students, lab technicians, and anyone studying microbiology. It provides a deep dive into the theoretical basis of Gram Staining (including the Cell Wall, Lipid, and Mordant theories) and a meticulous, step-by-step demonstration of the practical procedure, ensuring you understand every critical step from smear preparation to final microscopic observation.
Key Concepts & Step-by-Step Timestamps

Use the timestamps below to navigate to the specific theoretical and practical sections:

Theoretical Principles of Staining

[01:17] Gram-Positive vs. Gram-Negative: Understanding the structural differences in the cell wall (peptidoglycan layer) and their role in retaining the primary stain.

[03:28] Role of the Mordant (Gram's Iodine): Explanation of how the mordant forms a large Crystal Violet-Iodine Complex to aid in stain retention.

[07:05] Decolorization Theory: How Alcohol/Acetone affects the cell walls of Gram-Positive (dehydration) and Gram-Negative (lipid dissolution) bacteria.

[08:49] Final Interpretation: Identifying Gram-Positive (Violet) and Gram-Negative (Red/Pink) results.

Practical Demonstration & Procedure

[05:07] Smear Preparation & Fixation: Proper technique for creating a smear on a clean slide, mixing with saline, and Heat Fixing.

[06:07] Step 1: Primary Staining with Crystal Violet (1 Minute).

[06:40] Step 2: Mordanting with Gram's Iodine (1 Minute).

[07:05] Step 3: Decolorization with Acetone/Alcohol (Key technique: Just a few drops, immediately washed).

[07:39] Step 4: Counterstaining with Safranin (1 Minute).

[09:09] Essential Lab Safety: Proper handling of culture plates and sterilizing the inoculating loop (Flaming) without causing contamination.

[13:38] Morphology Observation: Critical instruction on using minimal colony material to preserve the bacterial shape (morphology) for clear viewing.

[19:33] Microscopic Observation: Using 100X with Cedarwood Oil for the final, definitive identification.


SANTINIKETAN MEDICAL COLLEGE & HOSPITAL
Real Classroom Demonstration/Lecture
On: MICROBIOLOGY by Dr. Chinmoy Bandopadhyay
(MBBS Batch: 2024-25)
Conducted on: 01-12-25