Escherichia coli  

Exam Cram

• Escherichia coli is a gram -ve rod, located in the bowel

• Commonly causes UTI, bacteraemia and traveller's diarrhoea

  • ETEC responsible for traveller's diarrhoea

  • EHEC: produces shiga toxin, causing haemolytic ureaemic syndrome (HUS)

• Antibiotics with good coverage: gentamicin, ciprofloxacin, trimethoprim & nitrofurantoin

Traveller's Diarrhoea

• Usually self resolving

• Requires only PO fluids and salt replacement, usually

• Classically caused in India or South East Asia

HUS (Haemolytic Uraemic Syndrome)

Background

• E.coli 0157 causes Gastroenteritis then HUS by production of a Shiga Toxin

• Shiga toxin causes haemolysis

Assessment

History

• 1-4d of diarrhoea & vomiting, sick contacts

• 24hrs: bloody diarrhoea, unwell

• Children > adults

Examination

• Abdo tender, soft

• Hypotensive

Investigations

• Haemolytic anaemia

  • Cell fragments

  • Increased reticulocytes & LDH

  • Low haptoglobin

• Raised creatinine

• Thrombocytopenia

• ADAMTS13- normal

• Stool testing for E.coli 0157 & Shiga Toxin

Diagnosis

Diagnostic criteria: clinical

Differentials: 

• TTP has acute neurology

• ITP is asymptomatic

• DIC has coagulopathy (raised INR, low fibrinogen)

Management

Acute

1. Supportive: IVF

Further notes

• Plasma exchange- contradictory information about use, consider if unwell. 

• FFP & monoclonal antibodies (Eculizumab, Ravulizumab) are rarely used. 

• Mortality is < 10% with IVF

Resources and References

1. https://www.msdmanuals.com/professional/hematology-and-oncology/thrombocytopenia-and-platelet-dysfunction/hemolytic-uremic-syndrome-hus

Written 2024