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45 Cards in this Set
- Front
- Back
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Mycobacterium TB infects
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humans
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Mycobacterium bovis infects
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cattle and other animals
why we pasturize milk |
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Mycobacterium microti infcets
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voles, mice, shrews
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Mycobacterium africanum infects
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humans (africa and europe)
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Mycobacterium leprae...
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leprosy
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Mycobacterium avium...
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pulmonary disese - HIV pts
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mycobacterium intracellular
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infects immunocomprimised
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General characteristics of mycobacteria
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weakly gram + - AFB
non-motile aerobic mycolic acid cell wall |
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What is unusual about the mycobacteria cell wall?
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1/3 of genome dedicated to lipid synth which makes the organism v. hydrophobic and resistant which is virulent
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what is unique to mycobacteria cell wall
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mycoic acid
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when you try to take a mycobacteria off a plate what would happen?
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it would crunch like a chip cause it is so dry and resistant
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What is the major reservoir for TB?
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only humans!
air borne |
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what is the leading cause of death due to a single microbial agent?
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m. TB
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if the immune response is robust to TB what happens
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walled off in a granuloma with no sx, contained
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if the immune response is not robust to TB what happens
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disease
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What happens if you have immune supression and a TB granuloma what happens
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reactive disease
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what are 2 strains of TB that are increasing in prevalence and are difficult to eliminate?
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MDR and XDR
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What are some reasons that worldwide incidence of TB is rising?
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inc pop
HIV epidemic travel metropolitan areas poorly managed TB programs |
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What does a multiplying TB lesion do?
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liquify
bacillary dissemination death |
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What does a latent TB lesion do?
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calcifies
latent potental reactivation |
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After TB is inhailed where does it go?
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ingested by a resident macrophage in deep lung tissue
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Probablility of bing a latent infection of TB?
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25%
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probablilty of reactivation of latent TB?
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1-2 yrs -> 5%
lifetime-> 10% |
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Sx of TB
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malaise
weight loss productive cough night sweats |
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different types of TB
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primary pneumonia
TB pleurisy cavitary TB miliary TB |
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Is latent TB infectious?
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no
with no observable signs of lesions on Xray |
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What is the immmune response to TB
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macrophages
foamy cells giant cells tcells |
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supression inf several cytokines contribute to reactivated disease in TB include
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TNF a
INF g iNOS |
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Active TB characteristics
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cough
weight loss infectious + ppd abnormal chest X ray + sputum test |
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Latent TB characteristics
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no sx
not infectious + ppd normal chest Xray and sputum |
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treatment for TB includes
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2 mo: insoniazid, rifampicin, ethambutol & pyrazinamide
4 mo: isoniazid & rifampicin 6mo: isonizaid & ethambutol |
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What is MDR?
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TB that is resistant to isoniazid and rifampicin
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What is XDR?
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resistant to isoniazid adn rifampicin and floroquinolone and others
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BCG vaccination causes
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+ ppd test
vaccination for TB |
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What's DOTs?
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direct obervational therapy short course
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What are the 5 components of DOTs?
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government commitment
case detection standarized tx uniterupted supply of drugs reporting and recording sys |
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How is Mycobacterium leprae transmitted?
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person to person via inhalation
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What has happened to m. leprae's genome?
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reduced to 50% of fxnal proteins
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What animal do you find m. leprae in?
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armidillos
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Pathogenesis of tuberculoidal leprosy
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strong cell immune response weak humoral response
few erythematous plaques extensive peripheral nerve damage not infectious |
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Pathogenesis of lepramatous leprosy
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strong humoral response weak cell response, lots of bacilli in dermal macropages adn in schwan cells
lots of plaques diffuse nerve involvement infectious |
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Mycobacterium avium
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from water and soil
HIV pts-> dissemintated not spread person to person |
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Mycobacterium bovis
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TB in cattle
why we pastruize milk inhailed and cause TB |
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Mycobacterium marinum
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oppertunisitic w skin lesions
from swimming pools and hot tubs disease in fish & frogs -> TB |
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What is the leporasy test (like ppd)?
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lepromin
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