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Staining Methods. Dr Ekta Chourasia Department of Microbiology. Types of Staining. Simple staining Differential staining Negative staining Impregnation method Special staining – for certain bacteria, bacterial spores, parasites & fungi. SIMPLE STAINS.
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Staining Methods Dr Ekta Chourasia Department of Microbiology
Types of Staining • Simple staining • Differential staining • Negative staining • Impregnation method • Special staining – for certain bacteria, bacterial spores, parasites & fungi Dr Ekta, Microbiology, GMCA
SIMPLE STAINS • Impart same color to all bacteria. • Only shows the presence of micro-organisms. • Retain bacterial morphology. e.g. Methylene blue, Carbol fuchsin , Safranine, etc Dr Ekta, Microbiology, GMCA
DIFFERENTIAL STAINS • Imparts different color to different bacteria. • Most widely used differential stains are: Gram stain & Ziehl Neelsen stain Dr Ekta, Microbiology, GMCA
Gram’s stain • It differentiates bacteria into two broad groups : Gram positiveGram negative – appear violet –appear red Dr Ekta, Microbiology, GMCA
Acid Fast Stain/ Ziehl – Neelsen Stain • Acid fast stain first described by Ehrlich. • Modified by Ziehl & Neelsen – used now. • For staining of mycobacteria • They have high content of Lipids (mycolic acid) Fatty acid in their cell wall Higher alcohols Dr Ekta, Microbiology, GMCA
NEGATIVE STAINS • Produce colored background against which bacteria stand out in contrast. • Used for bacterial capsule, spirochetes eg India ink, Nigrosin. Dr Ekta, Microbiology, GMCA
IMPREGNATION METHOD • Cell structures too thin to be seen under microscope are rendered visible by silver impregnation on their surfaces. • Used for the demonstration of bacterial flagella, spirochetes Dr Ekta, Microbiology, GMCA
Albert’s Stain • For staining of volutin granules containing organisms like diphtheria bacillus • The granules appear “red to violet” rest of the bacilli appear blue / greenish blue [metachromatic] Dr Ekta, Microbiology, GMCA
Giemsa Stain & Leishman Stain • For parasites causing Malaria Filaria Leishmaniasis etc. • Use for staining of peripheral blood smear. Dr Ekta, Microbiology, GMCA
Fluorescent Stain • Acridine orange • Fluorescein Isothiocyanate (FITC) • Auramine rhodamine Dr Ekta, Microbiology, GMCA
Fungal Stains • Lacto phenol cotton blue (LPCB) • Gram stain • Wright stain • Periodic Acid Schiff (PAS) • Hematoxylin Eosin (HE) • Methenamine silver etc. Dr Ekta, Microbiology, GMCA