Staining Techniques

Staining Techniques

Gram Staining

Schaeffer-Fulton Endospore Stain

Negative Stain

Welch Method

Ziehl-Neelsen/ Acid Fast Stain (Hot Method)

Kinyoun/Acid Fast Stain (Cold Method)

Gram Staining

Classify G(+) & G(-) bacteria

• Primary Stain: Crystal violet

Schaeffer-Fulton Endospore Stain

Identify presence of: endospore

• Primary Stain: Malachite green

→ (+) spore-forming: pink organisms with green dots

Negative stain

Identify presence of: capsule

• Primary Stain: India ink / nigrosin

Welch Method

Identify presence of: capsule

• Primary Stain: Crystal violet

Ziehl-Neelsen/ Acid Fast Stain

(Hot Method)

Identify: acid fast bacteria (ex. mycobacterium)

• Primary Stain: Carbol fuchsin

Kinyoun/Acid Fast Stain

(Cold Method)

Identify: acid fast bacteria (ex. mycobacterium)

• Primary Stain: Carbol fuchsin

Primary Stain

Crystal violet / Carbol fuchsin

Mordant

Gram’s iodine

Decolorizer

Alcohol / acetone

Counter Stain

Saffranin

Capsule Stain

• CuSO4: stains the capsule of the organism

• Visible result

→ (+) Violet organism with blue halo

Negative Stain

• For hard to visualize organisms

• Nigrosin: colors the environment

Special Stain

• Used for coiled, thin, and hard to visualize organisms

• Giemsa stain, silver stain (Treponema pallidum), Wright stain

Flagella staining

• STAIN: Unstable colloidal suspension of tannic acid

• Precipitates in the presence of flagella

Nucleoid staining

• STAIN: Feulgen Stain – sensitive for DNA