23. Shigella Flashcards Preview

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Flashcards in 23. Shigella Deck (25)
1

Disease caused by Shigella infection?

Bacillary dysentery (shigellosis)

2

3 species of Shigella that cause shigellosis?

S. dysenteriae, S. flexneri, S. sonnei

3

Shigella is a gram-______, ________cellular pathogen

Gram-negative

Intracellular pathogen

4

Which other studied pathogenic bacteria is Shigella similar to? How?

Salmonella

Actively invasive

5

Infectious dose of Shigella?

10-200 organisms

6

3 ways Shigella has features common to Salmonella/Listeria/pathogenic E.coli?

Uses T3SS effectors to control gap junctions

Causes active invasion

Causes membrane ruffling to invade host cells

7

What do Shigella hijack to cause the release of ATP from host cells?

Connexin 26 gap junction hemichannels

8

Purpose of causing ATP release?

Further increases bacterial invasion

9

What do Shigella use to control gap junctions?

T3SS effectors

10

Name of effector Shigella generates? What is it similar to?

IcsA

ActA in Listeria

11

Purpose of IcsA?

Recruits actin to propel bacteria around cytoplasm (huge comet tails)

12

4 F's of the fecal-oral route?

Food, fingers, feces, flies

13

Where does Shigella replicate?

Cytoplasm

14

How does the shiga toxin function?

A subunit can bind to host ribosomes => inhibits protein synthesis

15

What can the shiga toxin cause to the host?

Watery diarrhea (w/ blood, mucus, pus)

16

Shigella is resistant to many _______

antibiotics

17

Is there a vaccine against Shigella?

No

18

Which lab animal model is not susceptible to Shigella? Which will develop shigellosis? Which gives similar disease as in humans?

Not susceptible = mice

Develop shigellosis = young guinea pigs

Similar to humans = monkeys

19

What part of cells do Shigella target for efficient cell-to-cell spreading?

Tricellular junctions

20

What are tricellular junctions?

Junctions between multiple cells

21

Tricellular junctions use what protein to fuse adjacent membranes?

Tricellulin

22

How does Shigella move from cell to cell?

Couples tricellulin identification and clathrin-mediated endocytosis

23

Shigella is a gram-_____, ____cellular pathogen

gram-negative

INTRAcellular pathogen

24

Is shigella aerobic or anaerobic?

Anaerobic

25

What does Shigella do to host cells to allow themselves to enter?

Cause membrane ruffling