Infective gastroenteritis - Foodborne E.coli

Question 1

What is the epidemiology for E.coli?

Answer 1

· Affects are ages, races and both sexes.
· People at extremes of age and immunocompromised patients are more susceptible.
· Travellers to developing countries + infants at risk.

Question 2

What is the pathophysiology for E.coli?

Answer 2

· E coli is a gram-negative, rod-shaped bacterium.
· It’s a commensal that colonises the GI tract within a few hours of birth.
· E coli becomes pathogenic by acquiring virulence factors or genetic mutations.
· Infection occurs through ingestion, via contaminated food or water.
· Diarrhoea is caused by a combination of intestinal inflammation, loss of absorptive surface, increased mucosal permeability and ion secretion.
·Each pathological subtype of E coli exert a pathological response via different mechanisms.

Question 3

What is the prognosis for E.coli?

Answer 3

· Majority are asymptomatic or mild and self-limiting.
· In clinically apparent cases, most patients respond to supportive therapy, with recovery within 2-5 days.
· In children, acute gastroenteritis has a ↑ mortality due to dehydration.

Question 4

What is the aetiology for E.coli?

Answer 4

· The majority of E. coli infections are foodborne, accounting for:

• 80% of cases of enterohaemorrhagic E. coli infection - EHEC.
• 70% of cases of enterotoxigenic E. coli infection - ETEC.
• 30% of cases of other types of E. coli infection.

Question 5

What risk factors are associated with E.coli?

Answer 5

· Contaminated food products.
· Travel.
· Poor hygiene.
· Extremes of age (<5 and >60).
· Contact history.
· Immunosuppression.

Question 6

What signs and symptoms are associated with E.coli?

Answer 6

· Diarrhoea.
· Abdominal pain or discomfort.
· Volume depletion - dry mucous membranes and reduced skin turgor.
· Fever.
· N&V.
· Anorexia.
· Lethargy.

Question 7

What investigations would you do if E.coli was suspected?

Answer 7

· Stool cultures.
· FBC - raised WBC count, sometimes low Hb and/or platelets.
· U&E’s - raised urea, creatinine and hypokalaemia.
· CRP - raised.

Question 8

Suggest some differential diagnoses.

Answer 8

· Viral gastroenteritis.
· Amoebiasis.
· Non-infectious food poisoning.
· Ulcerative colitis.
· Crohn's.
· Non-infectious GI pathologies.

Question 9

What treatment options are available for E.coli?

Answer 9

· All patients:

• 1st line - Rehydration and supportive therapy.
• Adjunct - antimotolity agents - e,g, Bismuth.

· Suspected or confirmed enterotoxigenic:

• Adjunct - Abx.
• Adjunct - Antimotility agent.

· Confirmed enterohaemorrhagic:
- Plus - Notification of local or state health department.

Question 10

What complications can arise?

Answer 10

· Haemolytic uraemic syndrome:

• Haemolytic anaemia.
• Thrombocytopenia.
• AKI.
• Typically develops 5-9 days after diarrhoea onset.

· Bacteraemia.
· IBS.