Escherichia Coli

Question 0

Where in the body is E.coli normally found?

Answer 0

Colon.
Vagina.
Distal urethra.

Question 1

What does one associate with E.coli?

Answer 1

Faeces!

Question 2

How can E.coli in the vagina be problematic?

Answer 2

Infant acquire E.coli during birth > neonatal meningitis

*not same E.coli that causes enteric illness

Question 3

Which serotypes of E.coli are responsible for enteric illnesses?

Answer 3

EPEC
ETEC
EIEC
EAEC
EHEC

Question 4

What group are most likely to be infected with EPEC?

Answer 4

Infants *especially those < 1 yoa.

Question 5

How to prevent spread of EPEC?

Answer 5

Breast feeding - IgA, lactoferrin
*brewstfed babies have higher numbers of lactobacilli in their faeces (inhibit growth of EPEC)
Aseptic preparation of bottles and feeds
Strict hand-washing and good hygiene

Question 6

How does one treat a EPEC infection?

Answer 6

Fluid replacement.

Question 7

What is ETEC a major cause of? Who are usually involved?

Answer 7

Watery Diarrhoea in children.

*travellers Diarrhoea

Question 8

Toxins produced by ETEC?

Answer 8

Heat-labile toxin:
- similar to cholera toxin > elevated cAMP levels
Heat-stable toxin:
- elevated cGMP levels

Question 9

What do toxins produced by ETEC result in?

Answer 9

Altred ion transport and increased fluid excretion.

Dehydration + electrolyte imbalance + cardiovascular collapse if severe

Question 10

Can ETEC cause Diarrhoea by itself?

Answer 10

No, requires virulence factors (enterotoxins).

Question 11

How do ETEC colonise the small bowel?

Answer 11

Adhere to microvilli using pili(fimbriae).

Question 12

Why do travellers to an endemic area regarding ETEC get Diarrhoea but the locals do not?

Answer 12

Locals have antibodies to the fimbriae to local strains of E.coli that prevent adherence and colonization.

Question 13

How does one treat and prevent Diarrhoea caused by ETEC?

Answer 13

Supportive therapy.

Anti-biotic prophylaxis may be justified.

Question 14

What disease can EIEC cause and what disease is it similar to?

Answer 14

Dysentery-like syndrome:

• abdominal pain
• fever
• similar to shigellosis

Question 15

What may be found in the stool of someone experiencing dysentery?

Answer 15

Blood.
Mucus.
Polymorphonuclear leucocytes.

Question 16

How does one diagnose EIEC?

Answer 16

Large numbers of leucocytes in stools in the absence of other pathogens.

Question 17

What is EHEC also known as?

Answer 17

Shiga-toxin producing E.coli or Verotoxin-producing E.coli

Question 18

What is the commonest subtype of EHEC?

Answer 18

0157:H7

Question 19

What do ETEC produce?

Answer 19

Cytotoxin/Verotoxin identical to toxin produced by Shigella.

Question 20

What does EHEC cause?

Answer 20

Watery Diarrhoea > may rapidly progress to bloody Diarrhoea

Some patients > HUS

Question 21

Which type of E.coli can result in HUS?

Answer 21

EHEC

Question 22

What is HUS? Who is it more common in?

Answer 22

Haemolytic uremic syndrome

• haemolysis
• thrombocytopenia
• renal failure after onset of GIT symptoms
• more common in young children

Question 23

What extra intestinal illnesses can E.coli be responsible for involving the urinary tract?

Answer 23

Cystitis (inflammation of the bladder)
Pyelonephritis (inflam. of renal parenchyma, calyces, pelvis)
Asymptomatic bacteriuria

Question 24

What extra intestinal infections can E.coli cause?

Answer 24

Meningitis (neonate)
Pneumonia (compromised)
Peritonitis (perforations!)
Wound infection
Abscesses