Microscopy of clinical specimens

Purpose: Primarily used for rapid microscopic examination of

fresh specimens such as vaginal secretions to detect

budding yeast cells, hyphae, and pseudohyphae.

Saline Wet Mount

Application: Useful in candidiasis diagnosis.

Saline Wet Mount

Limitations: Does not kill organisms; structures may move,

and stain contrast is minimal.

Saline Wet Mount

Saline Wet Mount

Purpose: Ideal for staining and mounting cultured fungi, especially filamentous molds.

Lactophenol Cotton Blue (LPCB)

Components and Functions: Lactophenol Cotton Blue (LPCB)

•Phenol:

•Lacid:

•Cotton blue:

Kills organisms.

Preserves and clears fungal elements.

Stains chitin in fungal cell walls.

Application: Tease mounts and Scotch tape preparations are commonly made using LPCB to visualize structural features like

conidia, conidiophores, and hyphae.

LPCB

Purpose: Used for direct detection of fungal elements in keratinized tissue like skin, hair, and nails

Potassium Hydroxide (KOH) Preparation

Potassium Hydroxide (KOH) Preparation IS ENHANCED BY

Addition of Calcofluor white or Parker ink improves visualization

KOH

Purpose: Detects yeasts and pseudohyphae, particularly Candida spp

Use: Especially helpful in blood, sputum, and CSF samples for yeast detection.

Gram Stain

Appearance: Fungi generally appear

Gram-positive

Gram Staining

Purpose: Differentiates partially acid-fast organisms like Nocardia spp. from other filamentous bacteria and fungi.

Acid-Fast Stain

Acid-Fast Stain Modified by Kinyoun stain is called

Cold method for partially acid-fast organisms.

A fluorescent technique that enhances detection sensitivity.

Auramine-rhodamine stain:

Acid fast stain

Purpose: Demonstrates the polysaccharide capsule of Cryptococcus neoformans in CSF

India Ink (Negative Stain)

India Ink (Negative Stain) is largely replaced by

lateral flow antigen tests due to higher sensitivity.

India Ink

Purpose: Stains polysaccharides in fungal cell walls magenta.

Periodic Acid-Schiff (PAS) Stain

Application: Useful in tissue sections for invasive mycoses

Periodic Acid-Schiff (PAS) Stain

PAS

Purpose: Fluorescent dye that binds to cellulose and chitin in fungal cell walls

Calcofluor White Stain

In Calcofluor White Stain it is enhanced by

KOH

Higher than KOH or Gram stain for detecting fungal elements.

Calcofluor White Stain

Calcofluor White Stain