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Microbio: Stains
USMLE Step 1
Stain | Organism(s) |
---|---|
Ziehl Neelsen | acid fast bacteria, i.e. Mycobacterium tuberculosis |
India Ink | Cryptococcus neoformans |
Giemsa | Borrelia, Plasmodium, Trypanosomes, Chlamydia also blood smears |
Periodic Acid-Schiff (PAS) | tests for glycogen & mucopolysaccharides, used to dx Whipple's disease from the bacterium Tropheryma whipplei |
Prussian blue | blue dye test to detect Fe |
Congo red | stains amyloid red & causes amyloid to take up apple-green birefringence when viewed under polarized light microscope |
Osmic acid | fixative & stain for EM |
Gram stain | + for thick peptidoglycan (blue-violet) vs. - for thin peptidoglycan (pink-red) |