Shigella Flashcards
1
Q
General Characteristics
A
- g neg rod
- non motile or capsule
- fac anaerobe
- oxi neg, H2S neg
- Enterobacteraice
- ID50: 100-200 cells
- differenation via O-Ag
2
Q
DZ Progression:
Encounter, Entry & Spread, Mult, Damage, DX & TX
A
- Encounter: human reservior
- Entry & Spread: Person –> Person (fecal-oral)
- Mult: intcl growth on INTEST EPI cls (1o colon)
- Damage: Shigellosis –> GItis
Dysentary—> HUS - DX: select media, Physiological test, serotyping
- TX:
3
Q
T3SS
A
- encoded by ipa, mxi & spa genes
- secretes EFP into McPH & intest epi CLs
4
Q
Pathogenesis: Entry
A
- cant directly uptake
- forces up take
- host self inflicts inflam response
- induces McPH apoptosis & uptake via T3ss
5
Q
Pathogenesis: Induced Uptake
A
- secretion of EFP via T3SS into cells inducing cytoskeltal rearrangment
6
Q
Pathogenesis: Multiplication
A
- secretion of EFP into IEPICL inducing cytoskelatal rearrangment
- shig replicates in cytosol
7
Q
Pathogenesis: Spread
A
- shigella moves through cell wall avoiding reentering the intestine
8
Q
Effector Protiens:
- IpaA
- IpaB
- IpaC
- IpgD
- VirA
- IscA
A
- IpaA: premotes local actin depolu allowing for closing (engulfment, uptake)
- IpaB: induces apoptosis of McPH & prevents digestion, forms pore
- IpaC: forms pore
- ipgD: premotes actin pol (uptake)
- VirA: allows mass cytosketal change & membrane ruffling
- IscA: forms actin filaments propling through cell to cell
