Shigella

Question 1

what type of toxin is associated with shigella

Answer 1

complex AB toxin

Question 2

name the four types of shigella

Answer 2

s. sonnei
s. flexneri
s. dysenteriae
s. boydii

Question 3

describe symptoms of shigellosis

Answer 3

mucous, bloody diarrhea

Question 4

does shigellosis normally cause systemic infection?

Answer 4

no, typically is self-limting

Question 5

how is it transmitted?

Answer 5

via food and water

Question 6

is there a vaccine for shigella?

Answer 6

no

Question 7

which strain is the most severe?

Answer 7

s.dysynteriae

Question 8

what side of the cell does shigella attach to?

Answer 8

the basolateral side.

Question 9

adhesins associated with bacteria attachment are thought to be products of which genes?

Answer 9

ipaD and ipaB

Question 10

which cytoskeletal protein does the bacteria take advantage of?

Answer 10

actin

Question 11

what does the bacteria use actin for?

Answer 11

to move from cell to cell and to move within the cell

Question 12

explain how shigella enters the cells

Answer 12

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.

Question 13

where on the endothelial cell are the integrins located?

Answer 13

for shigella, the integrins are located on the basolateral side

Question 14

what type of plasmid is associated with a large virulence plasmid?

Answer 14

a large plasmid

Question 15

T3SS what is it

Answer 15

a complex protein structure which spans the two membranes of a gram negative bacterium.

Question 16

what does T3SS do?

Answer 16

forms an aqueous pore between bacteria and host cell cytoplasm.

Question 17

what are proteins secreted by T3SS called?

Answer 17

effector proteins

Question 18

Name bacteria where T3SS are found

Answer 18

EHEC and EPEC, Yersinia, salmonella, shigella

Question 19

which shigella strain uses a T3SS

Answer 19

S. Flexneri

Question 20

what does the needle-like structure of the T3SS do

Answer 20

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

Question 21

what is pyroptosis?

Answer 21

an inflammatory cell death.

Question 22

what does shigella do when it transverses M cells?

Answer 22

it kills macrophages to be released then into the basolateral side of the epithelial monolayer

Question 23

what is released after pyroptosis?

Answer 23

cytokines

Question 24

name three virulence factors of shigella which are adhesins?

Answer 24

ipaD&B, T3SS

Question 25

What does shigella do to actin?

Answer 25

it polymerises it to use it for motility

Question 26

what does ICSA do?

Answer 26

interacts with host N-WASP to polymerise actin, is not part of the T3SS.