Facultative intracellular/obligate anerobe???
- Produce Niacin but NO conversion --> free
- niacin accumulates will react with cyanogen bromide to form yellow-colored compound
Serpentine Cording: if colony is flattened and spread on microscope. B/c of cord factor glycolipid, trehalose 6,6’dimycolate
- Lowenstein-Jensen agar: egg yolk. B/c this is such a rich culture, it will grow MANY bacteria. So, they
- add malachite green dye to kill off the other bacteria.
Nitrate reductase positive
Heat labile catalase positive
Blood Agar: does NOT grow b/c it’s very fastidious
Auramine-rhodamine flourscent stain: pretty selectively binds mycobacteria (all)
- Hide in macrophage, inhibit: -phagosome/lysosome fusion
- -oxidative burst
- -acidification of phagosome
- -inflam cytokine response
- -MHC:C1 Ag presentation—no CTLs
Mycolic acids: allows bacteria to be acid-fast, very hydrophobic, it is like a shield.
Wax D, part of Freund’s adjuvant
Phosphatides: caseation necrosis
Exportative repetive protein: anti-phagocytic
CordFactor—trehalose dimycolate, this is related to the virulence b/c
Transmitted via resp droplets and is EXTREMELY contagious.
Milliary-stage, when disease disseminates to liver or spleen, creating many “millet seed” lesions.
- Dx: TST: PurProDeriv=mis of mycobacterial
- proteins. (+) test does NOT mean there is active or transmissible infection. Test result of Type 4 (delayed)
- hypersensivity. (+)>15mm induration, less if patient is immunocompromised.
- Granuloma: macro or mono eat pathogenàpresent
- to Th1 cell --> secrete IFN-g, TNF (damage lungs), macros secrete proinfoam cytokines (IL-1, IL-6, IL-2, TNF-a), macros form giant cell, poor
- granuloma=caseous necrosis
- Ghon complex comb of 1)single parenchymal lesion,
- 2)caseation resulting in calcified bronchial lymph node
- Exudative Lesion: acute inflammatory response@initial
Scrufola: mycobacterial cervical adenitis=unilateral cervical lymphnode tenderness.
GI TB: swallowing exudate
Oropharyngeal TB: painless ulcer
Renal TB: WBC in urine but no other culture.
Azicomycin affects the mycobacteria’s ability to make mycolic acids. CAT-G encodes for catalast peroxidase that activates Azinomycin.
Tx: isoniazid (some resistant b/c of chromosomal, point mutations), rifampin, pyrazinamide, ethambutol