M1 Micro Quiz 2 > E. Coli > Flashcards

E. Coli Flashcards

(60 cards)

Study These Flashcards
1
Q

what are the main serogroups of Enterohemorrhagic E. coli (EHEC, STEC)?

A 
O157:H7
O111
O26
O157:H-
O104:H4
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are the sources of EHEC & STEC infection?

A

food (undercooked/unpasteurized)
petting zoos
person to person
very low infectious dose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe Enterrohemorrhagic (EHEC & STEC) clinical syndrome.

A 
abdominal pain
bloody diarrhea
can lead to hemolytic uremic syndrome
acute renal failure (usu. children <10)
generally extracellular
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe Enterrohemorrhagic (EHEC & STEC) pathogenesis - what tools does the bacteria have to cause disease?

A 
pili-mediated attachment
T3SS
Intimin
recruit host cell actin causing altered morphology
shiga-like toxin
capsule
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the aspects of Enterrohemorrhagic (EHEC & STEC) virulence - what does it do in the body to cause disease?

A
  • actin disruption results in altered morphology and impacts signal transduction pathways forming A/E lesions
  • lesions lead to loss of microvilli (effacement)
  • Shiga like toxin disrupts eukaryotic protein synthesis and causes hemolytic uremic syndrome
  • hemolysin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is Tir? what does it allow E. coli to do?

A

a T3SS secreted bacterial protein that is delivered to surface of epithelial cells to allow for E. coli attachment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is Intimin? (E. coli)

A

Tir binding protein on surface of E. coli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is Shiga-like toxin? how is it toxic?

A

gene found on phage
disrupts eukaryotic protein synthesis via RNA cleavage activity
causes hemolytic uremic syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is Hemolysin? (E. coli) where is it encoded?

A

pore forming protein that inserts into host cell membrane

encoded by a plasmid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are the Diarrheagenic strains of E. coli?(5)

A 
Enteropathogenic (EPEC)
Enterotoxigenic (ETEC)
Enteroaggregative (EAEC)
Enteroinvasive (EIEC)
Diffuse adhering (DAEC)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How is Enteropathogenic E. coli (EPEC) transmitted?

A

Overt human pathogen transmitted by person-to-person contact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How it Enterotoxigenic E. coli (ETEC) transmitted?

A

From food and water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what type of e. coli produces a heat-labile toxin? how does this toxin act? what is the clinical consequence?

A

Enterotoxigenic E. coli (ETEC)

  • targets adenylate cyclase leading to increased cAMP levels that result in excess chloride ion secretion and blocked sodium ion uptake
  • leads to net loss of fluid and electrolytes in gut and watery diarrhea
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what type of e. coli produces a heat-stable toxin? how does this toxin act? what is the clinical consequence?

A
  • Enterotoxigenic E. coli (ETEC)

- alters cGMP levels leading to fluid and electrolyte loss through watery diarrhea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what types of disease does Enteroaggregative E. coli (EAEC) cause?

A
  • Diarrheagenic
  • Childhood diarrhea/Chronic diarrhea
  • persistent diarrhea that can lead to weight loss
  • No A/E lesions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how is Enteroinvasive E. coli (EIEC) transmitted?

A

From contaminated food

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what diseases does diffuse adhering E. coli (DAEC)? in what types of patients and where? what is know about it?

A

Diarrhea in older children in developing countries

poorly characterized

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

how would you diagnose E. coli?

  • what would you see in a lactose test?
  • sorbitol test?
  • immunoassay?
  • PCR?
A
  • Lac+
  • O157:H7 cannot grow on sorbitol while commensal E. coli are sorbitol-positive
  • Immunoassay for shiga-like toxin
  • do strain typing with PCR or DNA probe analysis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

how can you prevent E. coli spread and infection?

A
  • Hygiene

- Hay fed cattle are less likely to harbor E. coli than grain fed cattle due to higher stomach pH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

how are STEC & EHEC (Shiga toxin and Enterohemorrhagic) diagnosed?

A
  • PCR/immunoassay for shiga toxin
  • Nucleic acid detection of virulence genes
  • EHEC-sorbitol fermentation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

how is ETEC (Enterotoxigenic) diagnosed?

A
  • Nucleic acid detection of virulence genes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

how is EPEC (Enteropathogenic) diagnosed?

A
  • Nucleic acid detection of virulence genes or tissue culture assay for aggregative adherence
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

how is EAEC (Enteroaggregative) diagnosed?

A

Nucleic acid detection of virulence genes or tissue culture assay for aggregative adherence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

how is EIEC (Enteroinvasive) diagnosed?

A

Nucleic acid detection of virulence genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
how is DAEC (Diffuse adhering) diagnosed?
Tissue culture assay for diffuse adherence
26
Are Enteropathogenic toxins detected in stool?
No
27
Where and in whom is Enteropathogenic E. coli (EPEC) common? what does it cause?
- Leading cause of childhood diarrhea in developing countries - Forms A/E lesions - Diarrheagenic
28
how does Enteropathogenic E. coli (EPEC) adhere?
Localized adherence by bundle forming pili
29
what diseases does Enterotoxigenic E. coli (ETEC) cause?
- Diarrheagenic | - Traveler's Diarrhea
30
how does Enterotoxigenic E. coli (ETEC) adhere to cells?
Fimbriae adhere to receptors on enterocytes of small intestine
31
What are the toxins carried by Enterotoxigenic E. coli (ETEC)?
Head-labile toxin and Heat-stable toxin
32
what is the consequence of Enteroaggregative E. coli (EAEC) colonization factors?
colonization factors can lead to more aggressive epithelial cell attachment No A/E lesions
33
is Enteroaggregative E. coli (EAEC) invasive?
Non-invasive
34
what kinds of toxins does Enteroaggregative E. coli (EAEC) produce?
Heat stable-like toxin, Pet toxin, hemolysin
35
where is Enteroinvasive E. coli (EIEC) found?
Less common in industrialized nations
36
how does Enteroinvasive E. coli (EIEC) adhere to and invade cells?
attaches in colon by non-fimbrial adhesins | invades mucosal cells
37
is Enteroinvasive E. coli (EIEC) systemic?
non-systemic
38
what diseases does Enteroinvasive E. coli (EIEC) cause?
watery diarrhea with blood and mucus (similar to Shigella)
39
what toxins does Enteroinvasive E. coli (EIEC) produce?
Do not produce heat-labile or heat-stable toxin
40
how are STEC & EHEC (Shiga toxin and Enterohemorrhagic) treated?
- Supportive treatments | - Antibiotics contraindicated
41
how is ETEC (Enterotoxigenic) treated?
- Loperamide (can be combined with fluoroqinolones) - Azithromycin - rifaximin
42
how is EPEC (Enteropathogenic) treated?
Antibiotics guided by susceptibility testing for severe cases
43
how is EAEC (Enteroaggregative) treated?
Fluoroquinolones for travelers and HIV patients
44
Where and in whom is Enteropathogenic E. coli (EPEC) common? what does it cause?
- Leading cause of childhood diarrhea in developing countries - Forms A/E lesions - Diarrheagenic
45
how does Enteropathogenic E. coli (EPEC) adhere?
Localized adherence by bundle forming pili
46
what diseases does Enterotoxigenic E. coli (ETEC) cause?
- Diarrheagenic | - Traveler's Diarrhea
47
how does Enterotoxigenic E. coli (ETEC) adhere to cells?
Fimbriae adhere to receptors on enterocytes of small intestine
48
how does Enterotoxigenic E. coli (ETEC) respond to heat?
Head-labile toxin and Heat-stable toxin
49
what is the consequence of Enteroaggregative E. coli (EAEC) colonization factors?
colonization factors can lead to more aggressive epithelial cell attachment No A/E lesions
50
is Enteroaggregative E. coli (EAEC) invasive?
Non-invasive
51
what kinds of toxins does Enteroaggregative E. coli (EAEC) produce?
Heat stable-like toxin, Pet toxin, hemolysin
52
where is Enteroinvasive E. coli (EIEC) found?
Less common in industrialized nations
53
how does Enteroinvasive E. coli (EIEC) adhere to and invade cells?
attaches in colon by non-fimbrial adhesins | invades mucosal cells
54
is Enteroinvasive E. coli (EIEC) systemic?
non-systemic
55
what diseases does Enteroinvasive E. coli (EIEC) cause?
watery diarrhea with blood and mucus (similar to Shigella)
56
what toxins does Enteroinvasive E. coli (EIEC) produce?
Do not produce heat-labile or heat-stable toxin
57
how are STEC & EHEC (Shiga toxin and Enterohemorrhagic) treated?
- Supportive treatments | - Antibiotics contraindicated
58
how is ETEC (Enterotoxigenic) treated?
- Loperamide (can be combined with fluoroqinolones) - Azithromycin - rifaximin
59
how is EPEC (Enteropathogenic) treated?
Antibiotics guided by susceptibility testing for severe cases
60
how is EAEC (Enteroaggregative) treated?
Fluoroquinolones for travelers and HIV patients
M1 Micro Quiz 2
flashcards
Decks in class (12)
# Cards
Brainscape helps you reach your goals faster, through stronger study habits.
© 2026 Bold Learning Solutions. Terms and Conditions