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36 Cards in this Set
- Front
- Back
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What virus is driving the Tb epidemic? Where is this localized to?
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HIV/AIDS
Africa |
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What stain is used for a histologic diagnosis of Mycobacterium?
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Acid-fast
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What is the morphology of Mycobacterium?
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Bacilli
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What are the three unusual features of Mycobacterium?
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Slow growing; take 8 weeks to grow!
Obligate aerobes Mycolic acid in the cell wall; gives resistance |
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What occurs when Mycobacterium is in a low oxygen state?
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Enter a quiescent state and are resistant to cidal antimicrobials
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What are the layers within the M. tuberculosis cell wall?
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Outer to inner:
Capsule Mycolic acid Peptidoglycan/Arabinogalactan Inner membrane |
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What are the two enzymes involved in the biosynthesis of the mycolic acid in Mycobacterium that are targeted by antibiotics?
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KatG
InhA |
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What is the activity of KatG?
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Catalase/peroxidase
Required for clinical activity of Isonazid |
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What is the activity of InhA?
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Synthesis of long chain mycolic fatty acids.
Targeted by Isoniazid |
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What type of immunity is essential in controlling Tb infections?
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Cell-mediated immunity
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Primay Tb will show what signs on PPD and xray?
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PPD: +
Xray: - |
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Where is the first place that Mycobacteria localizes to in the body?
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Albeolar macrophages (dust cells)
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What is the mechanism by which Mycobacterium tuberculosis survives within macrophages?
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Blocking of P-L fusion.
No acidification; the cells can't be killed. |
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What does Mycobacterium tuberculosis do while inside the phagolysosome?
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Shed lipids that are presented to the body.
Are able to get out of the cell and stimulate the immune system. |
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What response is mycolic acid alone able to generate?
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Granuloma formation in the host.
Sufficient for virulence. |
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What is the function of TNF-alpha in Mycobacterium tuberculosis infection?
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Recruitment of macrophages
Stabilization of the granuloma |
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What kind of lymphocyte is active in Mycobacterium tuberculosis infection?
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CD4 TH1 cells
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What interleukin is produced by this T cell in Mycobacterium tuberculosis infection?
What is its activity? |
IL-2
Stimulation of CD8 cytotoxic T-cell development |
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What lymphokine is released by CD4 cells in T-cell Mycobacterium tuberculosis infection?
What is its activity? |
INF-gamma
Activation of macrophages |
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What molecules are released by activated macrophages in Mycobacterium tuberculosis infections?
What is their activity? |
IL-1
TNF-alpha Activation of a general immune response |
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What type of hypersensitivity reaction is active in Mycobacterium tuberculosis infections
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Type IV
Delayed; involves macrophages |
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What is the activity of CD8 T cells in Mycobacterium tuberculosis infection?
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Recognition and killing of infected macrophages
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What is the mechanism of dispersion of Mycobacterium tuberculosis from the lungs?
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Through regional lymph node
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That is the appearance on PPD/Xray for latent/dormant Tb?
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PPD +
Xray - |
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What is the most common form of Tb in the US?
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Latent Tb
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What is the effect of a weakening immune system on latent Tb?
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RELEASE OF THE BACTERIA!!!
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What are the Xray/PPD findings for active Tb?
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PPD +
Xray + SPUTUM + |
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Who are effected by disseminated/miliary Tb?
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Immunocompromised
Old Young |
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What is the mechanism of antigen presentation with Tb?
What is a complication with this? |
MHCI
Can't really use vaccines |
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What type of secretion system do Mycobacterium tuberculosis use?
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Type VI
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What is used for a Tb vaccine?
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Bacille Calmette Guerin
Avirulent strain of Tb from cows. NOT SAFE IN IMMUNOCOMPROMISED |
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What disease does Mycobacterium leprae cause?
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Leprosy
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What is the reservoir for Mycobacterium leprae?
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Humans
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What is the transmission of Mycobacterium leprae?
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Person to person via secretions, aersols.
Significant amounts of contact necessary |
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What is the appearance of a Mycobacterium leprae infection?
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Skin lesions.
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What type of Mycobacterium is found all over the place and has been implicated in infections in severely immunocompromised hosts?
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Mycobacterium avium complex
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