Foodborne E coli infection

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Last reviewed: September 2018

Last updated: March 2018

Summary

Most cases of Escherichia coli infection are foodborne.

In the US, the most common serotype of enterohemorrhagic E coli (EHEC) is O157:H7.

Enterotoxigenic E coli (ETEC) is the most common cause of traveler's diarrhea.

Diagnosis is made based on stool culture, with serotyping for greater specificity.

Treatment is supportive, with rehydration and correction of electrolyte imbalance.

Use of antibiotics is controversial and in most cases not necessary, except possibly in traveler's diarrhea.

Ten percent of patients with E coli O157:H7 infection develop hemolytic uremic syndrome.

Definition

Escherichia coli is a gram-negative, rod-shaped bacterium. It is a commensal that colonizes the gastrointestinal tract within a few hours of birth. E coli becomes pathogenic by acquiring virulence factors or genetic mutations, leading to a broad spectrum of disease. Infection by pathogenic strains occurs through ingestion, usually via contaminated food or water.

History and exam

Key diagnostic factors

diarrhea
hx of travel, contact with contaminated food, or contact with infected person

Full details

Other diagnostic factors

abdominal pain or discomfort
volume depletion
fever
nausea/vomiting
anorexia
lethargy

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Risk factors

contaminated food products
travel
poor hygiene
extremes of age (<5 years and >60 years)
contact history
immunocompromise
contact with infected animals

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Diagnostic investigations

1st investigations to order

stool cultures
CBC
renal function and electrolytes

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Investigations to consider

stool serotyping/PCR
blood cultures
inflammatory markers (CRP and/or ESR)
abdominal x-ray
endoscopy
abdominal CT scan

Full details

Treatment algorithm

INITIAL

all patients

ACUTE

confirmed enterotoxigenic positive

confirmed enterohemorrhagic positive

other Escherichia coli serotypes

Contributors

Authors VIEW ALL 

Alexandra Kent, MBBCh, MRCP

Specialist Registrar in Gastroenterology

St Mary's Hospital

London

UK

Disclosures

AK declares that she has no competing interests.

Satish Keshav, MBBCh, DPhil, FRCP

Consultant Gastroenterologist

Department of Gastroenterology

John Radcliffe Hospital

Oxford

UK

Disclosures

SK declares that he has no competing interests.

Peer reviewers VIEW ALL 

Andrew Poullis, BSc, MBBS, MD, FRCP

Consultant Gastroenterologist

St George’s Hospital

London

UK

Disclosures

AP declares that he has no competing interests.

Fiona Cooke, MA, PhD, MSc, FRCPath, MRCP, DTM&H

Research Fellow and Medical Microbiologist

Wellcome Trust Sanger Institute

Department of Microbiology

Addenbrooke's Hospital

Cambridge

UK

Disclosures

FC declares that she has no competing interests.

Houssam E. Mardini, MD, MPH, FACP

Voluntary Assistant Professor of Medicine

Digestive Health & Nutrition Center of Ashland

Ashland

KY

Disclosures

HEM declares that he has no competing interests.

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