Facts about Pathogenic Escherichia coli:

Question 1

what important common features does pathogenic Escherichia coli strains have?

Answer 1

• Lactose Fermenter (pink on MacConkey)
• Strict pathogens cause GI infections

Question 2

all strains will be identified using what E. coli biology facts?

Answer 2

Gram negative bacilli

Motile

Lactose fermenter

Oxidase negative

Catalase +

Question 3

what are the 4 clinical diseases Escherichia coli causes?

Answer 3

1) Entero Toxin E. coli (ETEC)
2) Entero Pathogenic E. coli (EPEC)
3) Entero-Invasive E. coli (EIEC)
4) Entero-Hemorragic E. coli (EHEC)

Question 4

how does EPEC spread?

Answer 4

fecal-oral in developing countries

Question 5

how does ETEC spread?

Answer 5

fecal-oral in developing countries

Question 6

how does EIEC spread?

Answer 6

fecal-oral in developing countries

Question 7

how does EHEC spread?

Answer 7

through fecal-oral found in beef or produce

Question 8

In ETEC, what is another name for entero-toxigenic E. coli?

Answer 8

traveler’s diarrhea

Question 9

what is another name for ETEC, other than traveler’s diarrhea?

Answer 9

Montezuma’s Revenge

Question 10

what does Entero-toxigenic E. coli do?

Answer 10

it attaches to the small intestine using fimbreae

Question 11

what 2 entero toxins will cause the symptoms seen with ETEC?

Answer 11

1. ​LT (heat-liable toxin)
2. ST (heat-stable toxin)

Question 12

what is the presentation of Entero-toxic E.coli?

Answer 12

self-resolving profuse watery secretory diarrhea without fever

Question 13

how does the LT toxin from ETEC cause diarrhea?

Answer 13

it increases levels fo cAMP through activation of adenylyl cyclase.

Question 14

how does the ST toxin cause profuse watery diarrhea in ETEC?

Answer 14

it activates guanylate cyclase and increases cGMP

Question 15

what is another name for EPEC (entero-pathogenic e.coli)?

Answer 15

Pediatric diarrhea

Question 16

where is EPEC common?

Answer 16

in developing countries

Question 17

what is the pathogenic mechanism of action in EPEC?

Answer 17

EPEC attaches to small intestine using T3SS (attaching and effacing lesions and kills microvilli.

leads to reduced absorption of water leading to symptoms

Question 18

how does EPEC present clinically?

Answer 18

self-resolving secretory watery diarrhea without fever

Question 19

what is another name for EIEC?

Answer 19

invasive diarrhea

Question 20

what is the pathological presentation of EIEC?

Answer 20

EIEC attaches to colon using fimbriae and it rockets from cell to cell causing severe destrion of epithelial layer and releases hemolysin killing RBC’s

Question 21

what is the clinical presentation fo EIEC?

Answer 21

dysentery (low volume bloody stool with WBC present) with high fever

Question 22

what is another name for EHEC?

Answer 22

hemorrhaging diarrhea

Question 23

outbreaks in the US is due to what?

Answer 23

bacteria uses cattle as a reservoir

Question 24

what is the pathological presentation of EHEC?

Answer 24

EHEC forms A/E lesions in the small intestine causing the diarrhea, then is uses shiga-toxin to destroy endothelial cells leading to the blood in the stool

Question 25

the shiga toxin found in EHEC, can spread to what other organ endothelial tissue?

Answer 25

kidney

Question 26

what is the clinical presentation of EHEC?

Answer 26

watery diarrhea followed by profuse bloody diarrhea without fever or WBC

Question 27

what can EHEC lead to after a while?

Answer 27

Hemolytic Uremic Syndrome

Question 28

what is EHEC serotype O157:H7 named after?

Answer 28

named based on LPS O and H antigen on its flagella

Question 29

is EHEC invasive? how is your answer related to fever?

Answer 29

no, which is why fever is most often absent

Question 30

what symptom is shiga-toxin responsible for?

Answer 30

it is responsible for the destruction of endothelial cells which leads to hemorrhaging

Question 31

what does shiga toxin do to kill intestinal villi?

Answer 31

cleaves hosts 28s RNA ribosome

Question 32

on who is hemolytic uremic syndrome most common?

Answer 32

5 years or less on TMP/SMX antibiotics

Question 33

what is the clinical presentation for hemolytic uremic syndrome?

Answer 33

thrombocytopenia Microangiopathic hemolytic anemia Neurological manifestations

Question 34

in EHEC, where will it not ferment? colonies will look how?

Answer 34

Sorbitol-MacConkey agar (S-Mac), colonies look white

Question 35

can other e.coli ferment Sorbitol-MacConkey agar (S-Mac)?

Answer 35

yes

Question 36

what e.coli is this?

Answer 36

EHEC

Question 37

on what food is EHEC mostly found?

Answer 37

burgers