Entero E. Coli

Question 1

Four main pathogenic strains E. coli:

how many serotypes?

Which is a dangerous one? and what does it cause?

Answer 1

EPEC (enteropathogenic E coli)

EHEC (enterohemorrhagic E coli)

VTEC (Verocytotoxigenic Escherichia coli)

STEC (Shiga toxin-producing E. coli)

100s of serotypes

E. coli 0157:H7

Hemorrhagic diarrhea, hemolytic-uremic syndrome (HUS)

Question 2

EAF and intimin are?

which then?

Answer 2

EAF and intimin are adherence factors

secretion of effector molecules, phosphorylation, and sequestration of actin molecules.

Question 3

What system does pathogenic E. Coli deliver its virulence proteins?

What does it do?

How?

Answer 3

Type III secretion system

the system translocates proteins directly from inside the bacteria into the host cell.

A channel is formed through both bacterial membranes by over 20 E. coli secretion complex proteins (Esc)

Question 4

What are the E. Coli secreted proteins and what do they do?

Answer 4

EspA= forms a filamentous translocation tube

EspB & EspD= form a pore in thehost cell membrane

Question 5

What is the Tir? What does it do?

Answer 5

Translocated intimin recpetor (Tir), with the help from the chaperone (CesT) is thought to travel through the channel to be inserted into the host cell membrane. It then binds its bacterial outer membrane ligand intimin.

Question 6

(TTSS)=

what does it form? which is comprised of? How far does it span?

Unique feature?

Answer 6

E. Coli type III secretion system

Forms a core “needle complex” composed of Esc proteins, that spans the bacterial inner and outer membrane (IM/OM) and the intervening periplasmic space.

a unique feature is a filamentous extension composed of a single polymeric protein, EspA is the secreted protein in which effectors are exported.

Question 7

EspD and EspB=

EspF and Map=

EspG and EspG2=

Map also does?

EspH=

Answer 7

two effectors, that form a plasma-membrane-integral translocon that is essential for effector delivery.

EspF and mitochondrial assoc protein (Map) disrupt tight junctions and mitochondrial function.

EspG and G2 target microtubules and indirecly activate RhoA.

Map also stimulates filopodia formation by mimicking signalling induced by activated Cdc42

EspH modulates the assembly kinetics and morphology of actin pedestals, possibly inhibiting Cdc42.

Question 8

ETEC delivery-

EPEC delivery-

EIEC delivery-

EHEC delivery-

Answer 8

enterotoxin delivery

actin bundle pedestal formation

“phagocytosis”

Shiga toxin delivery