Escherichia Coli Flashcards
Where in the body is E.coli normally found?
Colon.
Vagina.
Distal urethra.
What does one associate with E.coli?
Faeces!
How can E.coli in the vagina be problematic?
Infant acquire E.coli during birth > neonatal meningitis
*not same E.coli that causes enteric illness
Which serotypes of E.coli are responsible for enteric illnesses?
EPEC ETEC EIEC EAEC EHEC
What group are most likely to be infected with EPEC?
Infants *especially those < 1 yoa.
How to prevent spread of EPEC?
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
How does one treat a EPEC infection?
Fluid replacement.
What is ETEC a major cause of? Who are usually involved?
Watery Diarrhoea in children.
*travellers Diarrhoea
Toxins produced by ETEC?
Heat-labile toxin:
- similar to cholera toxin > elevated cAMP levels
Heat-stable toxin:
- elevated cGMP levels
What do toxins produced by ETEC result in?
Altred ion transport and increased fluid excretion.
Dehydration + electrolyte imbalance + cardiovascular collapse if severe
Can ETEC cause Diarrhoea by itself?
No, requires virulence factors (enterotoxins).
How do ETEC colonise the small bowel?
Adhere to microvilli using pili(fimbriae).
Why do travellers to an endemic area regarding ETEC get Diarrhoea but the locals do not?
Locals have antibodies to the fimbriae to local strains of E.coli that prevent adherence and colonization.
How does one treat and prevent Diarrhoea caused by ETEC?
Supportive therapy.
Anti-biotic prophylaxis may be justified.
What disease can EIEC cause and what disease is it similar to?
Dysentery-like syndrome:
- abdominal pain
- fever
- similar to shigellosis
What may be found in the stool of someone experiencing dysentery?
Blood.
Mucus.
Polymorphonuclear leucocytes.
How does one diagnose EIEC?
Large numbers of leucocytes in stools in the absence of other pathogens.
What is EHEC also known as?
Shiga-toxin producing E.coli or Verotoxin-producing E.coli
What is the commonest subtype of EHEC?
0157:H7
What do ETEC produce?
Cytotoxin/Verotoxin identical to toxin produced by Shigella.
What does EHEC cause?
Watery Diarrhoea > may rapidly progress to bloody Diarrhoea
Some patients > HUS
Which type of E.coli can result in HUS?
EHEC
What is HUS? Who is it more common in?
Haemolytic uremic syndrome
- haemolysis
- thrombocytopenia
- renal failure after onset of GIT symptoms
- more common in young children
What extra intestinal illnesses can E.coli be responsible for involving the urinary tract?
Cystitis (inflammation of the bladder)
Pyelonephritis (inflam. of renal parenchyma, calyces, pelvis)
Asymptomatic bacteriuria
What extra intestinal infections can E.coli cause?
Meningitis (neonate) Pneumonia (compromised) Peritonitis (perforations!) Wound infection Abscesses
