Demonstration Of Fungal Structures In Tissue Flashcards
Bloodstream invasion
Candidiasis
Example of non culturable
Lobomycosis and rhinosporidiosis
• Amount of tissue obtained
• Architectural distortion – tissue processing ?
• Diagnostic challenge – has mimics
Limitations
• All fungi show pink cytoplasm, blue nuclei, no color for the wall
Hematoxylin and eosin
• Detects glycogen in tissues, fungal walls contain large amounts of glycogen
• Fungal cell wall stain pink- red depending on counterstain
• Blue nuclei
Periodic Acid - Schiff Stain (PAS) –
silver nitrate outlines fungi in black due to the silver precipitating on the fungi cell wall. The internal parts of hyphae are deep rose to black, and the background is light green.
Grocott / Gomori Methenamine Silver Stain (GMS)
Stains mucopolysaccharides, including the capsules of a variety of organisms; also stains mucus, which can be present in a variety of human cells
• Stains capsules of Cryptococcus neoformans deep rose
Mayer or Southgate Mucicarmine Stain
stains the walls of most fungi; Hyphae and yeast stain dark blue or rose. Tissues stain deep blue and background is yellow.
Gridley stain
Useful to highlight the capsules of Cryptococcus, which appear red or blue depending on the stain used
Alcian Blue
simple, sensitive, and extremely specific method of detecting fungi in tissues or fluids. Applications for many different fungal organisms.
• Fluorescent Antibody Stain
used for blood and bone marrow specimens. Histoplasma capsulatum is an intra cellular organism, which appears as small oval to pear-shaped yeast-like cells with crescent shaped red- stained protoplasm surrounded by clear halo in segmented neutrophils
Giemsa stain
good for initial differentiation of dimorphic fungi. Works well on sputum smears.
Papanicolaou Stain
generally fungi are gram positive; Actinomyces and Nocardia are gram variable.
Gram Stain
used to differentiate the acid-fast Nocardia from other aerobic Actinomyces.
Modified Acid-Fast Stain
very popular for quick evaluation of fungal structures; will stain the chitin in cell walls of fungi.
Lactophenol Cotton Blue (LPCB)
demonstrates the capsule of Cryptococcus neoformans in CSF specimens.
• India Ink
Sporangia/ Spherules
• Rhinosporodiosis • Coccidioides
• Brain and subcutaneous abscess • dematiaceous
Phaeohyphomycosis
• Actinomycotic granule
• Eumycotic mycetoma
• Fine and delicate filaments or thick and septate hyphae
Granules
• Chromomycosis / Chromoblastomycosis
• Spherical
• Dematiaceous
• Splitting
• Sclerotic bodies
Fission Bodies
• In vivo – no chlamydospore
• Pulmonary x oral if hyphae»_space;>
yeast cells
• Renal candida
Combination of yeast cells and pseudohyphae
string of elongated blastoconidia formed by some yeasts that resemble a hypha-like filament.
Pseudohyphae
Describes as pilot wheel
Diagnosis: Paracoccidioides brasiliensism
North American blastomycosis aka
Blastomyces dermatitidis
Neutrophil in infected with (invade inside the neutrophil)
Histoplasma capsulatum
Coencytic
Zygomycete aseptate
Septate hyphae
Penicillium
Nonseptate hyphae
As in rhizopus
South american blastomycosis defined
as mouse ear or mariners wheel
Gram variable
Actinomyces and nocardia