Escherichia coli

Question 1

E. coli is found where

Answer 1

In intestine (most numerous as you move down the intestines) of animals as part of normal flora and in the environment from fecal contamination

Question 2

What is the specific type of organism is E. coli

Answer 2

Facultative anaerobic And may be opportunistic in nature

Question 3

What does it mean to call E. coli a pioneer species

Answer 3

It is one of the first organisms in a neonates intestinal flora that is picked up from the mother’s birth canal

Question 4

Morphology of E. coli

Answer 4

Grows on MacConkey agar and ferments lactose on plate and looks pink
Motile
Some strains are hemolytic
Grows best at 37 Celsius (human body temp)

Question 5

Steps of a gram stain

Answer 5

1. Make smear
2. Crystal violet (everything purple)
3. Iodine mordant to fix
4. Alcohol wash (decolorizes gram negative bacteria)
5. Safranin pink stain for gram negative

So gram positive is purple and gram negative is pink

Question 6

How are E.coli characterized

Answer 6

By serotyping which is sub grouping by surface antigens

Question 7

What are the antigens used to stereotype E.coli

Answer 7

O- lipopolysacharide
H- Flagella
K- capsule
F- fimbriae/pili

Question 8

What are the intestinal disease causing E. coli types- InPECs

Answer 8

Enterotoxigenic- ETEC
Enteropathogenic- EPEC
Enterohemorrhagic- EHEC
Enteroinvasive- EIEC

Question 9

What are the extraintestinal disease causing E. coli types- ExPEC

Answer 9

Uropathogenic- UPEC
CNS- NMEC
Septicemia- SEPEC
Respiratory- APEC

Question 10

How E.coli pick up virulence factors

Answer 10

Transposons, Pathogenicity Islands, Plasmids, Bacteriophages

Question 11

VIrulence factors that E. coli have

Answer 11

Flagella, fimbriae, needle factors that inject proteins in host cell to elicit changes (TTSS)

Question 12

EPEC virulence factor

Answer 12

Adheres to small bowel enerocytes and destroys the microvilli to create attach and make an effacing lesion (like sitting in a cup)

Question 13

EHEC Virulence factor

Answer 13

Makes the little cup (effacement lesion) like EPEC and then also has toxins that are transported into circulation

Question 14

ETEC Virulence factors

Answer 14

Attaches with fimbriae then releases 2 types of enterotoxins- heat-labile and heat-stable

Question 15

EIEC Virulence factor

Answer 15

Moves between cells because of actin fiber stimulation in the host cell

Question 16

UPEC Virulence factors

Answer 16

Must hold on in urinary tract- does so by fimbriae and acesnds because of motility
Also hemolyses

Question 17

APEC virulence factors

Answer 17

Attach and moves like UPEC, avian pneumonia, airsaculutis, pericarditis, cellulitis

Question 18

SEPEC Virulence factors

Answer 18

Gets into blood stream (septicemia), produces high numbers, and then produces toxins

Question 19

NMEC Virulence factors

Answer 19

Produce toxins to break tissue to cross blood brain barrier and digests part of brain- Cytotoxic necrotizing factor (CNF)

Question 20

Edema Disease in swine is caused by what and what do you see

Answer 20

Caused by EHEC and results in edema especially around eyes

Question 21

What causes pyrometra in dogs

Answer 21

UPEC strains

Question 22

Which example of E. Coli was given with cattle as a public health concern

Answer 22

EHEC