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