结核分枝杆菌(英文PPT).pdf
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Mycobacterium tuberculosis
(tubercle bacillus)
Biological properties
1. Morphology staining
*thin,straight or slightly curved rods
*acid-fast stain--red
*thick, complex, lipid-rich cell wall
*non-motile, non-spore
2. Culture
*obligate aerobe
*special nutrient requirement
yolk, glycerolmalachite green, potato
*slow growth
generation time -- 18h
primary isolation – 3~4 weeks
*colony -- “cauliflower”
*pellicle on surface of liquid media
3.Resistance
*resistant to : dry, acid, alkali
*sensitive to: moist heat, UV, alcohol
4.Variation
1) virulent variation - BCG
(Bacillus Calmette-Guerin)
➢ The vaccine contains a strain of live, attenuated M.bovis.
➢ Culture:yolk, glycerol(甘油), malachite green, potato
➢ 230 passages, 13years.
➢ BCG vaccine is effective in preventing the appearance of
tuberculosis, especially in children.
2) drug resistance variation
multidrug resistant TB (MDR TB ), a worldwide problem
Pathogenicity Immunity
➢ M.tuberculosis produces no invasive enzymes, no exotoxin and
does not contain endotoxin in its cell wall.
➢ The pathogenicity is likely caused by :
2. toxicity of bacterial components and metabolic products
3. immunopathological effects
➢ Pathogenic factor
(1) Lipid (closely related to virulence)
cord factor
1) binds to mitochondrial membrane, cause functional damage to
respiration and oxidative phosphorylation
2) inhibits migration of leukocyte
3) causes chronic granulomatosis
wax D
acts as an adjuvant resulting in delayed type hypersensitivity (DTH)
Phosphatide
Stimulate monocytes proliferation form tubercle
Inhibit proteinase form caseous necrosis
Sulfatides
inhibits the fusion of phagosome and lysosome in the phagocytes
(2) Protein
tuberculin combined with wax D DTH
2. pathogenesis
➢ Transmission occurs by the aerosol route but
also occur through other routes.
➢ Infectio
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