micro lab

Introduction

The acid-fast stain was developed in 1882 by Paul Ehrlich. Ehrlich was working with Mycobacterium tuberculosis, the bacilli responsible for tuberculosis, and found a technique that renders M. tuberculosis distinguishable from nearly all other bacteria. Acid-fast staining is, therefore, known as a differential stain. Mycobacterium and some Nocardia species are considered acid fast because, during the acid-fast procedure, they are able to retain the primary dye even when decolorized by a powerful solvent known as acid alcohol. Most other bacterial genera are easily decolorized by acid alcohol.
Ziehl/Neelsen Acid-Fast Staining Procedure
In later years, Ehrlich’s technique was improved upon by two microbiologists, Ziehl and Neelsen. Like Ehrlich, Ziehl and Neelsen’s procedure requires heat to force the primary dye through the cell wall. Another microbiologist, Kinyoun, developed a procedure in which a detergent is used as a wetting agent and heating becomes unnecessary.
Purpose: To identify members of genus mycobacterium
Materials:
• (2) Acid-fast Bacteria QA slides
• Acid-fast stain reagent ‘set’
• Carbolfuchsin
• Acid-alcohol (3% HC1 in 95% ethanol)
• Methylene blue
• Paper towel
• Stain Rack
• Clothes pin
• Bunsen burner
• Water bottle
• Striker
• Bibulous paper, Lens Paper

Methods:
1) Prepare bacterial smear preparation slide
2) Primary stain: Carbol Fushin
Lipid soluble & penetrates the cell
Uses heat (stream) to drive stain into cell
3) Decolorizer: Acid Alcohol decolorizes non-acid fast cells acid fast resist decolorization
4) Counterstain: Methylene blue
Non-acid fast cells (blue)
Acid fast cells (red)

Results:

Discussion:
Acid-fast organisms appear red, and background material appears blue

Introduction
The acid-fast stain was developed in 1882 by Paul Ehrlich. Ehrlich was working with Mycobacterium