Ch.10: Host Microbe Interactions and Pathogenesis Flashcards
Define: dysbiosis
- microbiota disruption
ex. ) antibiotics killing off normal microbiota in the gut
Define: tropism
- pathogens preference for a specific host (or specific tissue within the host)
- emerging pathogens expand their host or tissue range
Define: virulence
-the degree or extent of disease that a pathogen causes
Define: virulence factors
-ways pathogens overcome our defenses
streptokinase- dissolves fibrin clots and allows dissemination of the bacteria
coagulase- form a blood clot that protects from phagocytosis
hyaluronidase- enhances pathogen penetration through fissures
Define: attenuated pathogen
- lose virulence factors needed to cause disease
- infectious but weakened
- do not cause disease in a immunocompetent host
- sometimes used in vaccines
Define:ID50
- number of cells or virions needed to establish and infection in 50% of exposed hosts
- highly infectious pathogens have a lower ID50
Define: LD50
-amount of toxin needed to kill 50% of affected hosts that are not treated
Define: toxin
- molecules that generate a range of adverse host effects
- small amounts
- ex.) tissue damage and suppressed immune response
Define: toxemia
-presence of toxins in the blood
Define: endotoxin
- the lipid A region of lipopolysaccharide; poisonous to us and other animals and is mainly released by gram-negative bacteria when they die
- can cause septic shock in large amounts
- massive vasodilation (drop in blood pressure)
Define: toxigenic
-abilitiy of pathogens to produce toxins
Define: antitoxin
-produces by the host body and neutralize toxins
Define: exotoxin
- proteins produced during bacterial metabolism
- made by both gram positive and gram negative bacteria
- cause inflammation (fever)
Define: cytopathic effects
-effects that occur as pathogens establish themselves in the host and damage host cells; these effects can kill the cell (cytocidal) or simply damage it (noncytocidal)
Define: cytotoxins
How does change in the balance of microbes in the gut affect host-microbe interactions?
Different types of virulence factors
Table 10.3 and 10.4
Portals of entry and exit
Formation of a biofilm and quorum sensing
Quorum Sensing: the collective sensing and responding to changes within a bacterial community
What is invasiveness? Examples of invasins.
Invasiveness- ability for a pathogen to invade host tissues
How do pathogens evade immune defenses?
Biohazard Safety Levels
universal and standard precautions for clinical settings
