BIOL240 Lecture Notes - Lecture 5: Gram Staining, Kinyoun Stain, Mycobacterium
Document Summary
Differential stain used primarily in the identification of tuberculosis bacillus (mycobacterium tuberculosis) and leprosy genus (mycobacterium leprae) (do not stain readily by simple stain or. These bacteria have waxy cell walls because the walls contain large amounts of lipodial material (mycolic acid) which render the cell wall impermeable to most stains. Smear is heated to facilitate penetration of stain into bacteria. Smear flooded with carbolfuchsin (dark red dye contain 5% phenol) (has high affinity for lipid-rich material) Most bacteria except acid-fast microbes are decolorized by acid alcohol (therefore, acid-fast organisms) (acid-fast appears red) Methylene blue is used as counterstain in order for decolorized (non acid-fast) to be seen. Concentrations of phenol and carbolfuchsin are increased and detergent is added so heating isn t necessary. Bacillus megaterium -> acid fast negative (blue), rod-shaped.
