BACTERIAL PATHOGENESIS 2 Flashcards
what do virulence factors improve
confer an increased ability to cause disease
what are koch’s postulates to define virulence factors
how are bacterial virulence factors acquired?
through horizontal gene transfer
what are some examples of virulence factors
what are adhesins
present on bacteria, interact with the receptors on the target cells
how are receptor decoys used as anti virulence drugs
used to treat chronic UTIs
how do nutrient acquisition systems work (example of irons)
iron is really limited and is really important
hosts developed ways to sequester iron and keep it away from pathogens
how is the capsule a virulence factor
no capsule: your immune system can clear the infection naturally
what are virulence associated secretion systems
several types exist
we focus on type III secretion system (T3SS)
complex molecular machines
span bacterial and host membranes
allow for delivery of effector proteins (bacterial weapons) which are transported through hollow channel inside the syringe
powered by ATP
what are characteristics of T3SS
what do T3SS ressemble?
ressemble the flagellar basal body
how do different bacteria use T3SS differently?
what are the two categories of toxins?
what is LPS of gram negative bacteria?
endotoxin
how does LPS cause its effects?
sepsis=body’s reaction to LPS
what is an example of an exotoxin
causes botulism
what are the effects of botulinum toxin?
used in botox in very small quantities
you can get botulism from improperly processed canned food
what are characteristics of exotoxins
what are categories of exotoxins?
characteristics of AB toxins
A= toxic activity
B= binding to target on host cell
how do membrane disrupting exotoxins work
key differences between exo and endotoxins
what are intoxications
what is an example of intoxication
characteristics of enterohemorrhagic e.coli (EHEC)
enterohemorrhagic e.coli
what is EHEC illness
how does EHEC’s T3SS work
EHEC remains extracellular
T3SS is the main interference with the host cell
injects Tir, which becomes a receptor for EHEC inside the host cell
also injects ~30 other proteins which dissociate tight junctions between intestinal epithelial cells, block host phagocytic pathways and interfere with host immune response
EHEC is very tightly associated with the host cell now
what is Shiga toxin
what does shiga toxin cause when it is present in different parts of the body?
why cattle carry EHEC asymptomatically
how is EHEC treated?
how can EHEC be prevented?
