MICI 4218 Lecture Notes - Lecture 24: Carbol Fuchsin, Mycobacterium Tuberculosis Complex, Kinyoun Stain
12 May 2021
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Mici 4218 lecture 24 march 15, 2021 mycobacteria. Objectives: review mycobacteria in general: how are they different from other bacteria, acid fast stains types, tb: epidemiology, disease, pathogenesis, diagnosis, treatment. Mycobacteria: aerobic, non-spore forming, bacilli (rod shaped, slowly grow in bacterial culture (1-8 weeks, ~200 species of mycobacteria, although the diseases that they produce are distinct there are features shared by all mycobacteria, tuberculosis complex: bsl-3 organisms. Normal cell wall and mycobacterial cell wall have a lipid bilayer, peptidoglycan, polysaccharides, and outer lipid layer. However, only mycobacteria have a mycolic acid and lipoarabinomannan (lam) layer. Acid fast bacteria retain the carbol fuchsin stain due to the mycolic acids in their cell wall. In a typical acid-fast protocol for mycobacteria, we would start with a sputum sample, which contains mucus and normal flora. In the first step, biochemicals are added to digest the mucus to release the organism from the mucus.
