Differential Staining

Gram staining

Christian Gram

by ?

Certain bacteria have thicker peptidoglycan such that when they are stained with primary dye they are not easily decolorized and thus retain the primary stain while bacteria with thinner peptidoglycan are easily decolorized but retain the secondary stain

Acid Fast staining

Paul Ehrlich

also known as Ziehl-Neelsen Method

by ?

• Some bacteria are able to resist decolorization by acid alcohol (acid fast) due to the presence of lipids that bind tenaciously with the primary stain

• Identifies Mycobacteria and Nocardia, organisms that have waxy materials in their cell wall (mycolic acid)

• Endospore stain

• Flagella stain

• Cytoplasmic inclusion stain'

• Capsule stain

• Anthony’s method

• Albert stain

Stains for Special Structures

Endospore stain

demonstrates spore structure in bacteria as well as free spores

E.g., Schaeffer-Fulton method

• Malachite green as primary stain

• Safranin as secondary stain

Capsule stain

demonstrates presence of capsules surrounding cells; also known as negative-staining;

E.g., nigrosin or India ink

Anthony’s method

• Crystal violet as primary stain

• Copper sulfate as decolorizer

Flagella stain

demonstrates presence and arrangement of flagella

• Mordants: Tannic acid and potassium alum

• Stain: Pararosaniline (Leifson method) or basic fuchsin (Gray method)

Cytoplasmic inclusion stain

identifies intracellular deposits of starch, glycogen, polyphosphates, hydroxybutyrate and other substances.

Anthony’s method

A type of Capsule staining where you use positive and negative dye instead of only negative dye.

Positive dye to stain the cell without staining the capsule

Crystal violet, Lugol’s Iodine, Acetone alcohol, Safranin

Gram staining

primary stain, mordant, decolorizer, and secondary stain?

Carbol fuchsin, Acid alcohol, Methylene blue

Acid fast staining

primary stain, decolorizer, and secondary stain?

Malachite green and Safranin

Endospore stain

primary stain and secondary stain?

India ink or Nigrosin

Capsule staining or negative-staining

primary stain?

Crystal violet and Copper sulfate

Anthony’s method

primary stain and decolorizer?

Tannic acid and potassium alum

Pararosaniline (Leifson method) and Basic fuchsin (Gray method)

Flagella stain

Mordant then Stain?

Albert staining

A staining technique used to identify metachromatic granules in Corynebacterium diptheriae

• Toluidine blue

• Malachite green

• Glacial acetic acid

• Alcohol (95% ethanol)

Albert A solution consists of:

• Iodine

• Potassium iodide

Albert B solution consists of:

Most capsules of bacteria made up of carbohydrates

Bacillus anthracis is made up of proteins

FACT