Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Veterinary Bacteriology & Mycology > Escherichia > Flashcards

Escherichia Flashcards

1
Q

What is the structure of Escherichia coli? In what oxygen conditions does it live in? What is it able to ferment?

A

Gram-negative rodes with peritrichous flagella

facultative anaerobes

glucose and lactose —> pink on MacConkey

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

How does E. coli respond to oxidase and catalase tests?

A

oxidase negative
catalase positive

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

What is E. coli’s most common habitat? Is it antimicrobial resistant?

A

normally live harmlessly in the intestinal tract of all mammals

yes - β-lactams and fluoroquinolones

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

What surface antigens are used to serotype E. coli? What 2 serotypes of E. coli are known to be extremely dangerous?

A
  • fimbrial antigens (F)
  • capsular antigens (K)
  • flagellar antigens (H)
  • somatic/LPS antigen (O)
  1. E. coli O157:H7
  2. E. coli O18:K1:H7
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the main 4 intestinal (diarrheagenic) E. coli and where are they found?

A

SMALL BOWEL
1. enterotoxigenic E. coli (ETEC)
2. enteropathogenic E. coli (EPEC)

LARGE BOWEL
3. enterohemorrhagic E. coli (EHEC)
4. enteroinvasive E. coli (EIEC) - human pathogen

(enteritis + diarrhea)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What fimbrial adhesins are present in Enterotoxigenic E. coli? What is their function?

A

F4*, F5, F6, F41

attachment to the small intestine

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

What 2 enterotoxins do enterotoxigenic E. coli secrete? What do they do?

A
  1. heat-labile enterotoxin (LT)
  2. heat-stable enterotoxin (ST)

increase cGMP and cAMP levels within small intestine epithelial cells, causing water and electrolytes to secrete from the cell —> watery diarrhea

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

What pathogen causes neonatal diarrhea? What is the most common host? What are 3 symptoms?

A

enterotoxigenic E. coli

newborn calves, lambs, and piglets within the first week of life (receptors aren’t resistant to ETEC yet)

  1. diarrhea
  2. severe dehydration
  3. death
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is enteric colibacillosis treated? Controlled?

A

enterotoxigenic E. coli —> neonatal diarrhea

  • milk with fluids containing electrolytes
  • feeding ample amounts of colostrum shortly after birth for resistance (antibiotics not recommended)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What pathogen(s) cause post-weaning diarrhea? What is the most common host? What are 3 symptoms?

A

enterotoxigenic E. coli or enteropathogenic E. coli

pigs within 1-2 weeks after weaning

  1. watery diarrhea
  2. loss of appetite
  3. purplish discoloration of the skin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

In what 3 ways is post-weaning diarrhea controlled/treated?

A
  1. vaccination
  2. breeding for disease resistance
  3. antibiotics following a susceptibility test
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What adhesin is present in enteropathogenic E. coli? How is it able to translocate internal toxins and proteins into host cells?

A

intimin

type 3 secretion system

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

How does enteropathogenic E. coli cause watery diarrhea?

A

pedestal formation on small intestine epithelium leads to the loss of microvilli and causes attaching and effacing lesions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What surface structures contribute to enterohemorrhagic E. coli virulence? Where does it colonize?

A
  • intimin (ahesion)
  • T3SS
  • attaching and effacing lesions
    (like EPEC)

large bowel (colon)

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

What toxin is unique to enterohemorrhagic E. coli? What does it do?

A

Shiga toxin - causes hemorrhagic diarrhea and kidney failure

  • EHEC = Shiga toxin-producing E. coli (STEC) = verocytotoxin-producing E. coli (VTEC)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Cattle are the primary reservoir of EHEC E. coli O157:H7, but they remain healthy. Why?

A

Shiga toxins bind to globotriaosylceramides (Gb3) found in the kidneys and intestine of humans, but are absent in cattle

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

What kind of disease does enterohemorrhagic E. coli cause? How is it able to do this?

A

edema disease in pigs within 1-2 weeks after weaning

Shiga toxin-producing (O138, O139, O141, O147) that binds to Gb4

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

What are 5 symptoms of enterohemorrhagic E. coli-caused edema disease in pigs?

A
  1. swelling (edema) of eyelids
  2. muscle tremors
  3. unusual squeal or snoring sounds
  4. neurological dysfunction
  5. flaccid paralysis and death within 36 hrs onset of clinical symptoms
19
Q

What is enteroinvasive E. coli? What allows it to colonize the large bowel?

A

flagella lacking intracellular pathogen in the colon

ipaH (invasive) gene and T3SS

20
Q

What are the 2 most common signs of enteroinvasive E. coli infection? What is the most common host?

A
  1. inflammation, necrosis, and ulceration of the bowel
  2. watery to bloody diarrhea (dysentery) with fever

humans —> dogs and cats resistant

21
Q

What are the 4 most common extraintestinal pathogenic E. coli (ExPEC)?

A
  1. septicemic E. coli (SEPEC)
  2. avian pathogenic E. coli (APEC)
  3. uropathogenic E. coli (UPEC)
  4. mammary pathogenic E. coli (MPEC)
22
Q

What type of E. coli causes colisepticemia? What are the most common hosts? How does it cause disease?

A

septicemic E. coli

newborn calves, lambs, and poultry, or immunocompromised animals

invades the bloodstream to cause systemic infection

23
Q

What are 5 virulence factors of septicemic E. coli?

A
  1. serum resistance (necessary to avoid complement and leukocytes in the blood)
  2. fimbrial adhesins
  3. aerobactin iron uptake system
  4. LPS
  5. cytotoxic necrotizing factors (CNF)
24
Q

What are the most common signs of colisepticemia in calves, lambs, and horses/dogs/cats?

A

CALVES: pyrexia, depression, weakness, hypothermia, prostration, meningitis, pneumonia, arthritis

LAMBS: watery mouth disease, death

HORSES/DOGS/CATS: pneumonia

25
Q

What is septicemic E. coli the most common cause of?

A
  • meningitis
  • pneumonia
  • arthritis

able to invade bloodstream and spread

26
Q

What pathogen causes avian colisepticemia?

A

(systemic disease of birds and poultry)
avian pathogenic E. coli
- serotype O1, 2, 18, 35, 36, 78, 111

27
Q

What are the 4 major virulence factors of avian pathogenic E. coli?

A
  1. type 1 (F1) and P fimbriae
  2. LPS
  3. serum resistance
  4. aerobactin iron uptake system
28
Q

What are 4 common signs of avian colisepticemia?

A
  1. septicemia
  2. salpingitis
  3. pneumonia and airsacculitis
  4. egg yolk peritonitis
29
Q

What are 2 common signs of uropathogenic E. coli infection?

A
  1. cystitis
  2. pyelonephritis
30
Q

What 6 virulence factors are present in uropathogenic E. coli?

A
  1. type 1 pili - attachment to uroepithelium
  2. hemolysin A
  3. LPS
  4. CNF1
  5. aerobactin - kidney infection
  6. capsule - kidney infection
31
Q

How is uropathogenic E. coli able to evade host defense and antimicrobials?

A

undergo the formation of intracellular bacterial communities or quiescent intracellular reservoirs

32
Q

What are 4 common conditions in dogs caused by uropathogenic E. coli? Why are females more likely to become infected?

A
  1. cystitis - inflammation of the bladder
  2. pyelonephritis - inflammation of the kidney
  3. pyometra - inflammation of the uterus
  4. prostatitis - inflammation of the prostate

females have shorter urethras, making it easier for the bacteria to reach the bladder

33
Q

Does uropathogenic E. coli have zoonotic potential?

34
Q

What does mammary pathogenic E. coli commonly cause? What are the 2 most common sources of infection?

A

infection of the mammary glands of cows and sows —> mastitis

  1. fecal contamination of the skin of the mammary gland
  2. relaxation of the teat sphincter following milking
35
Q

What are the 3 most common pathogens causing mastitis in cattle? What are 3 clinical signs?

A

E. coli, Steptococcus uberis, Staphylococcus aureus

  1. swelling of the udder, pain, redness
  2. fever
  3. reduced milk production and quality
36
Q

What are 2 ways to treat mastitis in cattle?

A
  1. broad spectrum intramammary antibiotic tubes
  2. nonsteroidal anti-inflammatories (NSAIDs)
37
Q

What specimen can be collected for E. coli isolation?

A
  • cervical swabs, vaginal discharge (pyometra)
  • milk (mastitis)
  • urine (cystitis)
  • blood (septicemia)
  • feces (enteritis with diarrhea)
38
Q

How does E. coli grow in blood agar, MacConkey agar, EMB agar, and chromogenic agar?

A

BLOOD: hemolytic
MACCONKEY: pink (lactose and glucose fermentation)
EMB: metallic sheen
CHROMOGENIC: dark blue

39
Q

How does E. coli respond to the IMViC test?

A

indole +
methyl red +
Voges-Proskauer -
citrate -

40
Q

How are ETEC and EPEC strains of E. coli specifically identified?

A

ETEC
- enterotoxin: ELISA
- virulence genes LT, ST, EAST, F4: PCR
- fimbrial antigens: latex agglutination test

EPEC
- urease +
- virulence gene eae: PCR
- histopathological examination: effacement of mucosal surface

41
Q

How are STEC (edema disease), SEPEC, and UPEC strains of E. coli specifically identified?

A

STEC
- clinical and PM findings: bloody/watery diarrhea
- hemolytic on blood agar
- serotype O139 and 141
- virulence genes eae, stx2e

SEPEC
- isolation from blood
- colicin V plasmids for serum resistance

UPEC
- isolation from urine
- type 1 pili (fimH)

42
Q

What is the recommended treatment for E. coli infection? How is infection controlled?

A
  • rehydration + electrolytes
  • antibiotic therapy if infection is severe or systemic

~ feeding colostrum after birth
~ reduce stress during weaning
~ hygiene
~ vaccines for enteric disease in piglets and mastitis in dairy cows

43
Q

E. coli summary:

Veterinary Bacteriology & Mycology (47 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions