Microbiology Staining Techniques and Principles

Practice vocabulary flashcards covering microbial staining methods, Gram stain characteristics, and isolation techniques based on lecture notes.

Endo Spore Stain Primary Stain

malachite green

Endo Spore Stain mordant

steam, used because the spore is resistant

Endo Spore Stain decolorizer

DI water

Capsule Stain Primary Stain

Congo red

Capsule Stain decolorizer

DI water

Acid-fast Stain Primary Stain

Carbol fuchsin

Acid-fast Stain mordant

Steam

Acid-fast Stain Counter stain

Methylene blue

Acid-fast Stain decolorizer

acid-alchol

Simple Stain

Stains including methylene blue, crystal violet, & safranin that are basic and $\text{+ charged}$; specimens are Air dried & then heat fixed.

Negative Stains

Stains including congo red, India Ink, & nigrosin that are acidic and $-\text{ charged}$ ; specimens are Air dried.

Gram Positive

Bacteria that retain the Primary Stain due to a thick cell-wall and appear Purple.

Gram negative

Bacteria that lose the Primary Stain and appear Red/Pink

Gram stain Primary stain

Crystal Violet

Gram stain mordant

Gram's iodine

Gram stain Counter / secondary Stain

Safranin

Endospore Appearance

green Structures w/ red cell walls

Capsule Appearance

fuschia rods w/ clear capsules & red backgroud

Acid-fast Appearance

red

Non-acid fast Appearance

blue

Mycolic acid

A waxy compound in the cell wall of mycobacteria that allows them to resist drying, disinfectants, and multiple antibiotics.

3 Main Purposes of Staining

1. Enhance contrast to see cells & structures 2. Identify structural differences (e.g., gran stain) 3. Reveal biochemical differences based on substances within the cell.

Streak Plate

The fastest, simplest, & most widely used technique for separating bacteria with the purpose of isolating colonies.