Term
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Definition
direct deposition beneath skin
bites, cuts, biological vectors, injections |
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Term
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Definition
| number entering that results in 50% probability of infection and disease in test subjects |
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Term
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Definition
lethal dose for 50% of sample population
Usually much greater than the ID50 |
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Term
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Definition
initial attachment to host cells is a requirement for infection by most pathogens
Attachment is usually specific for host and tissue/cell type
can result in biofilms |
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Term
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Definition
molecule on surface of microbe that binds to a specific molecule on surface of the host
Usually a protein
Basis for host range and specificity of some pathogens |
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Term
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Definition
Adherence
Penetrance
Toxins |
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Term
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Definition
Special cell wall component
of Streptococcus pyogenes
Adherence to epithelial cells to avoid phagocytosis |
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Term
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Definition
Waxy lipid that helps mycobacterium resist digestion after phagocytosis.
this can help them reproduce inside of of the phagocyte. |
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Term
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Definition
| proteins that promote entry into host cells |
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Term
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Definition
promote blood clotting
Wall off infection site from host defenses
Some Streptococci |
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Term
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Definition
dissolve clots
Break out of confinement
Staphylokinase and streptokinase |
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Term
| Hyaluronidase and Collagenase |
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Definition
break cell-cell connections and destroy tissue integrity
Allow penetration of epithelial layers.
Some streptococci and clostridia |
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Term
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Definition
destroy antibodies
Neisseria gonorrhoeae |
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Term
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Definition
high frequency of structural changes in molecules recognized by immune system
High mutation / recombination frequency |
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Term
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Definition
proteins secreted from the bacterial cell
Some very harmful in small amounts (low LD50)
antigenic: vaccines developed against some |
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Term
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Definition
Significant role in virulence of some gram negative pathogens.
Significant in opportunistic infections by gram negative bacteria.
Danger associated with perforation of large intestine or ruptured appendix.
Large numbers of gram negative bacteria in normal microflora of large intestine. |
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Term
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Definition
exotoxin
B subunit: binds to specific target molecule on host cell surface and mediates entry into cytoplasm
A subunit: toxic effect on cell |
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Term
| Membrane Disrupting Toxins |
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Definition
(type II) exotoxin
may be targeted to specific call types |
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Term
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Definition
type I exotoxin
stimulate an intense immune response that damages host tissues
S. aureus
enterotoxin responsible for staph food poisoning
toxin responsible for toxic shock syndrome |
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Term
| features that toxin names relate to |
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Definition
tissue affected
bacteria that secretes it
effect |
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Term
| Lipid A component of LPS molecules |
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Definition
Low toxicity: high LD50
non-antigenic: no immunity to endotoxin
heat-stable: not easily inactivated by high temperature
non-specific: effects can be caused by any gram negative bacteria in blood or tissue fluids
can be released if bacterial cell lysis occurs |
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Term
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Definition
stimulates abnormally large release of cytokines from macrophages and some leukocytes.
Fever
Shock: vasodilation and increased blood vessel permeability causes drop in blood pressure
called septic shock if due to endotoxin
Abnormal clot formation blocks some vessels |
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