Shigella Flashcards
(26 cards)
what type of toxin is associated with shigella
complex AB toxin
name the four types of shigella
s. sonnei
s. flexneri
s. dysenteriae
s. boydii
describe symptoms of shigellosis
mucous, bloody diarrhea
does shigellosis normally cause systemic infection?
no, typically is self-limting
how is it transmitted?
via food and water
is there a vaccine for shigella?
no
which strain is the most severe?
s.dysynteriae
what side of the cell does shigella attach to?
the basolateral side.
adhesins associated with bacteria attachment are thought to be products of which genes?
ipaD and ipaB
which cytoskeletal protein does the bacteria take advantage of?
actin
what does the bacteria use actin for?
to move from cell to cell and to move within the cell
explain how shigella enters the cells
attaches to basolateral side using products of the genes ipaD and ipaB. Transverses across the M cells to macrophages. kill the macrophages, released, bind to epithelial cell, invades, spreads, damages and causes bloody diarrhea.
where on the endothelial cell are the integrins located?
for shigella, the integrins are located on the basolateral side
what type of plasmid is associated with a large virulence plasmid?
a large plasmid
T3SS what is it
a complex protein structure which spans the two membranes of a gram negative bacterium.
what does T3SS do?
forms an aqueous pore between bacteria and host cell cytoplasm.
what are proteins secreted by T3SS called?
effector proteins
Name bacteria where T3SS are found
EHEC and EPEC, Yersinia, salmonella, shigella
which shigella strain uses a T3SS
S. Flexneri
what does the needle-like structure of the T3SS do
it forms a pore in the host cell membrane, makes the initial contact with the host. shigella then injects the proteins to interact with the actin cytoskeleton
what is pyroptosis?
an inflammatory cell death.
what does shigella do when it transverses M cells?
it kills macrophages to be released then into the basolateral side of the epithelial monolayer
what is released after pyroptosis?
cytokines
name three virulence factors of shigella which are adhesins?
ipaD&B, T3SS
