E.Coli

Question 0

e.coli is what type of bacteria

Answer 0

enteric!

Question 1

e.coli are part of

Answer 1

normal microflora (esp in newborns)

Question 2

e.coli synthesizes

Answer 2

vitamin K

Question 3

two types of strains of e.coli

Answer 3

shiga toxin producing (STEC)

diarrheagenic (the rest)

Question 4

different enteropathogenic e.coli have different

Answer 4

virulence factors

Question 5

main serogroup

Answer 5

O157:H7

Question 6

other EHEC (enterohemorrhagic) serogroups

Answer 6

O111, O26, O157: H-

Question 7

sources of infection

Answer 7

Food
Petting zoos
person to person contact
very low infectious dose

Question 8

clinical syndrome of EHEC

Answer 8

abdominal pain
bloody diarrhea
hemolytic uremic syndrome
acute renal failure in severe cases

Question 9

most cells of EHEC

Answer 9

remain extracellular ((some can invade mucosal) but does NOT become systemic

Question 10

why does hemolytic uremia syndrome happen in HUS?

Answer 10

destruction of red blood cells and damage to lining of blood vessel walls

Question 11

EHEC has what type of attachment

Answer 11

pili-mediated

Question 12

T3SS induces

Answer 12

formation of attaching/effacing lesions

Question 13

genes for T3SS are encoded…

Answer 13

LEE pathogenicity island (locus for enterocyte effacement)

encodes intimin and tir

Question 14

Tir

Answer 14

t3SS secreted bacterial protein that is delivered to surface of epithelial cells to allow for e.coli attachment

Question 15

intimin

Answer 15

Tir binding protein on surface of e.coli

Question 16

other e.coli proteins..

Answer 16

recruit host cell actin–>causes altered morphology–>impacts signal transduction pathways in the host cell to form A/E lesions

Question 17

Lesion can lead to

Answer 17

effacement (destruction of host cell microvilli)

Question 18

Hemolytic uremia syndrome is due to activity of

Answer 18

shiga-like toxin

Question 19

why are cow not suceptible to EHEC?

Answer 19

SHiga toxin binds Gb3/CD77 host glycolipid by the B subunit and this receptor is not present in cattle

Question 20

hemolysin

Answer 20

pore forming protein that inserts into host cell membranes
common in the E.coli strains that cause meningitis
encoded by a plasmid

Question 21

E.coli also have.. (3 things)

Answer 21

capsule (k-antigen)
LPS
nutrient aqusitions pathways

Question 22

EPEC

Answer 22

diarrheagenic e.coli

Question 23

EPEC is transmitted via

Answer 23

person to person contact

Question 24

how is EPEC transmitted?

Answer 24

person to person contact

Question 25

what does EPEC do?

Answer 25

forms A/E lesions

Question 26

toxins in EPEC

Answer 26

not detected in stool of infected human volunteers

Question 27

ETEC

Answer 27

enterotoxigenic E. coli

Question 28

where/when is ETEC an issue?

Answer 28

traveler's diarrhea | problematic in infants in the developing world

Question 29

how does ETEC work?

Answer 29

fimbriae adhere to specific receptors on enterocytes in small intestine

Question 30

Heat-labile toxin

Answer 30

targets adenylate cyclase -->increase cAMP-->excess chloride ion secretion-->blocked Na ion uptake **net loss of fluid and electrolytes into lumen of gut and watery diarrhea

Question 31

Heat stable toxin

Answer 31

alters cGMP levels-->net loss of fluid and electrolytes into lumen of gut and watery diarrhea

Question 32

EAEC

Answer 32

enteroaggregative ecoli

Question 33

EAEC logistics

Answer 33

childhood diarrhea similar to EPEC, common in developing countries

Question 34

EAEC compared to EPEC

Answer 34

somewhat more aggressive due to different colonization factors that lead to more aggressive epithelial cell attachment

Question 35

EAEC does not have

Answer 35

A/E lesions -->non invasive

Question 36

what does EAEC contain?

Answer 36

heat stable-like toxin (EAST) poorly characterized plasmid encoded toxin (PET) hemolysin

Question 37

EIEC

Answer 37

enteroinvasive

Question 38

how does EIEC path work?

Answer 38

attaches to cells within the colon by non fimbrial adhesions--> invades mucosal cells--> multiplies within these cells **does not become systemic**

Question 39

clincal syndrome of EIEC

Answer 39

water diarrhea that can contan blood and mucous

Question 40

genes for EIEC

Answer 40

genes for invasion, replication within host, and survival are encoded by a plasmid

Question 41

what is different about EIEC?

Answer 41

they do NOT produce shiga toxin or LT

Question 42

DAEC

Answer 42

diffuse adhereing ecoli

Question 43

what does DAEC cause?

Answer 43

diarrhea in older children in many developing countries

Question 44

E.coli and lac

Answer 44

lac+

Question 45

O157:H7 and sorbital

Answer 45

sorbital negative, but other commensal E. coli strains are sorbitol-positive

Question 46

prevention e.coli

Answer 46

grass fed cattle carry a lot, so we need to reduce carriage (hay feeding and probiotics) hygene