STEC infection in children

STEC infection should be highly suspected in children with acute bloody diarrhoea, even if only one episode contains blood.

Children under 5 are most susceptible to STEC infection.

STEC infection is uncommon. Consideration should also be given to more common gastrointestinal infections such as Campylobacter, Shigella and Salmonella and non-infective pathology such as intussusception and inflammatory bowel disease.

Complications like HUS are more common in children.

Prompt public health action is crucial because of the risk of person-to-person spread.

Suspect STEC in a child or young person with:

• acute bloody diarrhoea
• diarrhoeal illness with known STEC risk factors.

Follow the flowchart for management of acute bloody diarrhoea or clinically suspected STEC infection in children age <16 years.

Assess for:

• dehydration
• severe illness features eg frequent bloody diarrhoea, severe abdominal pain, vomiting, pallor, petechiae, oliguria, blood and protein on urine dipstick^7,19,20,21
• epidemiological risk factors
• alternative diagnoses (especially requiring surgery).

If STEC is suspected based on clinical features or risk factors:

• Stool sample: urgently send a stool sample for culture, notifying the laboratory of urgency.
• Provide relevant clinical history, particularly any history of bloody diarrhoea, on the stool culture request.
• As well as details of bloody diarrhoea, other relevant clinical history should be included on the form e.g. HUS, contact with case, part of an outbreak investigation.
• If clinical history is suggestive of STEC (bloody diarrhoea, HUS, contact with a case), carry out PCR testing to detect Shiga toxin (stx) genes.
• If HUS is indicated, diagnostic laboratories should refer stool samples to SERL on the day of receipt or next business day, pending local culture.

If STEC is suspected or confirmed:

• Urgent referral: Refer the child to paediatrics for HUS assessment.
• Public health notification: notify the local public health team immediately, even before test results. 

• Advise the household contacts, especially those with young children, on hygiene and control measures (cleaning, food handling). A patient information leaflet is available to download and public health can provide further support.
• Manage any close contacts with diarrhoea promptly as suspected cases of STEC.
• Advise symptomatic people to remain away from childcare, school and work for at least 48 hours after symptom resolution.
• High-risk groups (young children, food handlers, those working with vulnerable groups and high-risk groups living in the same household as an infected child) will require longer exclusion and guidance from public health.¹

Public health will contact the family to investigate the infection source and provide advice on preventing spread and returning to childcare, school and work.

Approximately 15% of children with STEC infection develop HUS.^2,3 HUS is associated with an acute mortality of 2–5%. While the kidneys are primarily affected, other organ systems can also be involved.

Clinical presentation:

• neurological symptoms: irritability, encephalopathy, seizures, focal neurological symptoms and signals
• renal involvement: acute kidney injury.

Timing of HUS onset: Typically, 6-8 days after the onset of diarrhoea, often as diarrheal symptoms are improving. However, it can occur up to 14 days after the initial infection,^2,22 and even after apparent recovery.

Assessment and monitoring:

• Assess and monitor for dehydration.

• Order blood and urine tests to assess for dehydration and potential HUS (as recommended in Table 1).

• Stool sample: If STEC is not confirmed, urgently send a stool sample for culture, notifying the laboratory of urgency.

• Provide clinical history, particularly details of bloody diarrhoea, and other relevant clinical history e.g. HUS, contact with case, part of an outbreak investigation, on the stool culture request.

• If clinical history is suggestive of STEC (bloody diarrhoea, HUS, contact with a case), undertake PCR testing for both E. coli O157 and non-O157 STEC.

• If a local PCR is positive, but local culture is unsuccessful, the stool should be referred to SERL.

• If a local PCR is negative, but the patient is presenting with HUS or acute bloody diarrhoea and is causing clinical concern, discuss referral of stools for further testing with SERL.

• Implement mandatory infection-control measures immediately.

Intravenous fluid therapy:

Monitor fluid balance closely and consult paediatric nephrology if there's concern about fluid overload or developing HUS.

• Notify the local public health team immediately, even before test results are available.
• Advise household contacts on hygiene, environmental cleaning and food handling practices (especially with young children). Public health can provide further support.
• Inform parents that public health will contact them to investigate the infection source, prevent spread and guide childcare, school or work return.

Symptom management:

NSAIDs should be avoided because of potential adverse effects on renal blood flow and increased risk of kidney injury.²⁸

Clinical judgement: Antibiotic use should be limited to specific clinical indications unrelated to STEC infection and should be discussed with an infection specialist.

Postinfection monitoring:

• Renal replacement therapy: Approximately 50% of children with HUS will require dialysis.^34,35
• Long-term outcomes: While most children recover, there's a risk of long-term complications like hypertension and chronic kidney disease.^36,37,38

• Supportive care: Supportive therapy, including fluid and electrolyte balance, dialysis where indicated and blood pressure control, remains the preferred treatment.^39,40

• Plasma exchange: There is currently insufficient evidence to recommend plasma exchange for STEC-associated HUS.^39,40
• Eculizumab: There is currently insufficient evidence to recommend eculizumab for rescue therapy in STEC-associated HUS. While eculizumab was used in the 2011 European E. coli outbreak, the results were mixed, with no definitive positive effect on clinical outcomes from eculizumab reported.^41,42,43,44 Eculizumab therapy was often given when there was severe neurological involvement or persistence of HUS despite plasmapheresis therapy. There was some evidence that in children with typical HUS and central nervous system (CNS) involvement, early use of eculizumab was associated with good neurological outcome, but in patients with rapidly progressing HUS and multiple organ involvement, eculizumab seemed to be less beneficial.

Give parents and families the STEC Patient Information Leaflet. Advise them that the following require prompt medical assessment:

• bloody diarrhoea (especially if new)
• repeated vomiting
• severe abdominal pain or cramps
• decreased urination or smaller urine amounts
• increased weakness or fatigue
• cold hands and feet
• pale appearance
• petechiae (tiny red or purple spots on skin)
• swelling, especially around eyes, legs or feet
• headache.

Provide emergency healthcare contact details.

Direct parents and families to parent and patient information about HUS.