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16 Cards in this Set
- Front
- Back
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1. Organism must be found in diseased animal, not healthy
2. Organism must be isolated from diseased animals & grow in pure culture away from animal 3. Organism must reproduce disease when reinoculated into animals 4. Organisms should be reisolated from experimentally infected animals |
Koch's postulates
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Degree of pathogenicity
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Virulence
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Property that enhances the ability of an microorganism to cause disease
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Virulence factor
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Host colonized with pathogen, but no overt symptoms of diease.
Can still be infectious |
Carriage
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Infectious agent present, not growing, but can reactivate
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Latent
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# of organisms required to cause disease
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Infectious dose
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-LPS
-OM of gram - -at low concentrations: immunostimulant -at high concentrations: hypotension & shock |
Endotoxin
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Both Gram - & + produce extracellular protein toxins that are critical virulence factor
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Exotoxins
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AB subunit exotoxins
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A- active unit
B- binding unit Act by enzymatic rxn called ADP-ribosylation |
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Hydrolyze membrane phospholipids & destabilize CM
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Cytolysins
-phospholipases |
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Forms pores in membrane allowing entry of water--> cell lysis
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Cytolysins
-pore-forming toxins |
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Forms bridge btw MHC class iI of Macrophages & receptors on t cells
Activates a large subset of T cells and get massive response |
Superantigen
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induced to take-up bacteria via receptor mediated endocytosis
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non-professional macrophage
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-Invasin binds to host receptor and zips host CM
-requires host cell signaling via Tyrosine Kinase -Causes disruption of host CM |
Zipper mechanism
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-Type III secretion injects protein into host-->ruffling-->explosion to engulf bacteria-->causes no disruption of CM
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Trigger mechanism
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Unique only for L. pneumophilia
Coils from around organism & phagosome "sinks" into cell |
Coiling phagocytosis
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