15. Pathogenic E. coli

Question 1

How many serotypes of pathogenic E. coli?

Answer 1

> 700, based on cell surface antigens

Question 2

3 types of diseases caused by pathogenic E. coli?

Answer 2

• Intestinal disease (gastroenteritis)
• UTIs
• Neonatal meningitis

Question 3

5 types of pathogenic E. coli that can cause intestinal disease?

Answer 3

HPTIAgg

Entero..

EHEC (hermorrhagic)
EPEC (pathogenic)
ETEC (toxigenic)
EIEC (invasive)
EAggEC (aggregative)

Question 4

Which type of pathogenic E.coli causes traveler’s diarrhea?

Answer 4

EPEC (pathogenic)

Question 5

Which type of pathogenic E.coli affects people the most?

Answer 5

EHEC

Question 6

Pathogenic E.coli transmission and duration?

Answer 6

Contaminated food, ppl-to-ppl

Usually 7 days

Question 7

2 strategies E. coli 0157:H7 uses to create diarrhea?

Answer 7

1. Injected effectors

2. Shiga toxin

Question 8

Why would a pathogen want to cause diarrhea?

Answer 8

To disseminate into the environment

Question 9

4 mechanisms of diarrhea generation by pathogenic E. coli?

Answer 9

1. Breach of tight junctions
2. Alteration of water channels (aquaporins)
3. Alteration to serotonin functions
4. Alteration of ion channels

Question 10

What does pathogenic E.coli do to tight junctions that will eventually cause host diarrhea?

Answer 10

E.coli secretes bacterial effector proteins (EspF, EspG, Map)

E.coli secreted protein and mitochondria affected protein

Question 11

How does the alteration of water channels cause diarrhea?

Answer 11

Only a single water molecule can pass through the channel at a time

Also uses EspF and EspG which rips water channels out

Removes AQP2 and AQP3 from the membrane

Question 12

How does the alteration of serotonin functions cause diarrhea?

Answer 12

Works on the nervous system of the intestine

Question 13

How does the alteration of ion channels cause diarrhea?

Answer 13

Shiga toxins attach to receptors => cause signaling cascades that alter the functions of ion channels => ions and water are released from the cell

Question 14

Why would the host have trouble detecting pathogens being secreted from E. coli?

Answer 14

E. coli T3SS needle shields them

Question 15

Pathogenic E. coli is a _____cellular pathogen

Answer 15

extracellular

Question 16

EHEC can cause diarrhea but can also lead to a kidney disease called..?

Answer 16

HUS (hemolytic-uremic syndrome)

Question 17

EHEC O157:H7 was first isolated where and in what year?

Answer 17

Argentina, 1977

Question 18

What is the function of a E. coli pedestal?

Answer 18

Unknown

Question 19

Hallmark of pathogenic E. coli disease?

Answer 19

The pedestal

Question 20

Potent toxin that E.coli releases?

Answer 20

Shiga toxin

Question 21

Shiga toxin is a specific host site ______

Answer 21

exotoxin

Question 22

Shiga toxin target?

Answer 22

Intestine

Question 23

Kiyoshi Shiga first discovered the shiga toxin in a pathogen called…?

Answer 23

Shigella dysenteriae

Question 24

2 things that shiga toxin can do?

Answer 24

• Target both epithelial and endothelial (blood vessel) cells
• Cause diarrhea and loosen blood vessels => blood release

Question 25

4 problems that diarrhea can cause

Answer 25

• Dehydration
• Loss of ions
• Hemorrhage (with O157:H7)
• Potential for death

Question 26

What are inside E. coli pedestals?

Answer 26

Actin filaments

Question 27

Pathogenic E.coli collapse host cell ________

Answer 27

microvilli

Question 28

What is the nervous system of the intestine called?

Answer 28

Enteric nervous system

Question 29

Which type of pathogenic E.coli secretes shiga toxin?

Answer 29

EHEC

Question 30

3 ways of delivering effectors?

Answer 30

On bacterial surface

Directly into host cytoplasm

Secreted (toxins)