Clinical Bacteriology Lab: Capsule, Spore, and Flagellar Staining

This set of vocabulary flashcards covers the clinical laboratory procedures and terminology for capsule, spore (Schaeffer-Fulton), and flagellar (Leifson) staining techniques.

Capsule

A discrete, organized covering that protects some pathogenic organisms, made up of polysaccharide polymers and polypeptides.

Capsule Appearance

Appears as a clear or halo-like area surrounding the organism against a stained amorphous background when using India ink or nigrosin.

Capsule Function

Acts as a virulence factor by inhibiting phagocytosis.

Klebsiella pneumoniae

The organism used in the capsule staining procedure to be mixed into a drop of India ink.

Capsule Procedure Precaution

Do not heat fix or blot dry, as heating will destroy the capsule.

Spore

Multilayered, ovoid or spherical structures found inside Gram-positive bacteria, produced in response to adverse conditions and nutritional deprivation.

Spore-forming Genera

Gram-positive bacteria such as Bacillus and Clostridium.

Calcium dipicolinate

The main component of a spore, also referred to as the dipicolinic acid calcium complex.

Schaeffer-Fulton method

The most common technique used to demonstrate endospores in the laboratory.

Malachite green

The primary stain for endospores, used as a $6.5\%$ aqueous solution and heated until steam rises.

Safranin O (Spore Staining)

The counterstain used for $30$ seconds in the Schaeffer-Fulton method to stain vegetative cells red or pink.

Leifson staining technique

A common method used by microbiology laboratories to stain flagella.

Basic fuchsin

The primary stain used in the flagellar staining procedure.

Tannic acid

The mordant used in flagellar staining to help visualize the flagella.

Atrichous

A classification for a bacterial cell that is devoid of flagella.

Monotrichous

A classification for a bacterial cell that possesses $1$ flagella on one pole or end.

Lophotrichous

A classification for a bacterial cell that possesses a tuft or group of flagella on one pole or end.

Amphitrichous

A classification for a bacterial cell that possesses $1$ flagella on both poles or ends.

Peritrichous

A classification for a bacterial cell that is surrounded with flagella.

Golden precipitate

A film that forms on the dye surface during Leifson staining indicating the smear is ready to be washed with distilled water.