Guidance

Shiga toxin-producing Escherichia coli: complications

Updated 20 December 2017

The following conditions are complications of shiga toxin-producing Escherichia coli (STEC), also known as vero cytotoxin-producing Escherichia coli (VTEC).

1. Gastroenteritis

Some people infected with STEC have typical gastroenteritis symptoms, specifically diarrhoea with or without vomiting, abdominal cramps and fever. Symptoms may last a few days and then disappear within a week or so. Management of cases is purely supportive; antibiotics are not recommended and might exacerbate the sequelae of infection. ¹

If a case is suspected, have a stool sample collected and send it to the local hospital laboratory where it will be tested for the presence of presumptive VTEC O157 and report the case to the local health protection team. Reporting is mandatory under the Health Protection (Notification) Regulations 2010. Screening of contacts and exclusion from school or work may be necessary upon advice from the health protection team.

2. Haemorrhagic colitis

The toxins released by STEC strains and their ability to adhere to and damage the intestinal epithelium can cause patients to develop an inflamed colon which bleeds a lot, resulting in very bloody diarrhoea and severe abdominal pain. Often there’s no fever with haemorrhagic colitis. Symptoms can be severe and may last for several days but typically clear completely within 2 weeks.

The burden of STEC infection is greater in children and guidance for healthcare practitioners in England relating to the management of acute bloody diarrhoea potentially caused by STEC in children was published in July 2011.

Although STEC is a rare cause of enteric disease, the probability of a case of bloody diarrhoea having STEC infection is much higher than in non-bloody diarrhoea and must be considered as an important indicator that STEC infection may be present. In addition, clinicians should have a high index of suspicion of STEC infection where the patient has been in recent close contact with ruminants, their faeces or faecally contaminated environments such as open farms, where there has been contact with another known or suspected STEC case or where an outbreak of STEC is known or suspected locally.

The guidance recommends that in children up to the age of 16, where symptoms are acute and frank blood is present a history of multiple episodes is not required and referral for specialist paediatric advice should be made on the evidence of a single episode.

3. Haemolytic uraemic syndrome (HUS)

It is thought that up to 10% of cases infected with STEC develop HUS after an initial period (a prodrome) of gastroenteritis or haemorrhagic colitis. It most commonly develops in young children or the elderly. The receptors for Vero cytotoxins are present on epithelial cells, particularly in kidney tissue and in the central nervous system. The toxins damage endothelial cells generating thrombin and fibrin deposits in the microvasculature. This goes on to cause leakage and tissue oedema. Erythrocytes are damaged as they pass through small vessels partially occluded by thrombus and haemolysis subsequently occurs. Fewer than 5% of childhood HUS cases die.²

4. Thrombotic thrombocytopaenic purpura (TTP)

Some people (mainly adults) infected with STEC develop TTP. This may present as flu-like symptoms (prodrome) including fever, fatigue and generalised malaise and arthralgias. Then a patient may present with some or all of the classic symptoms including: thrombocytopaenia (with petechial haemorrhages in the lower extremities and a tendency to bleed), other haematological changes (anaemia), fever, renal changes (gross haematuria, microscopi haematuria, raised urea and creatinine) and neurological deficits.

5. References

1. Wong CS, Jelacic S, Habeeb RL, Watkins SL, and Tarr PI. The Risk of the Hemolytic-Uremic Syndrome after Antibiotic Treatment of Escherichia coli O157:H7 Infections. N Engl J Med 2000; 342:1930-6.

2. Lynn R, O’Brien S, Taylor CM, Adak BA, Chart H, Cheasty T, Coia JE, Gillespie IA, Locking ME, Reilly WJ, Smith HR, Waters A, Willshaw GA. Childhood Hemolytic Uremic Syndrome, United Kingdom and Ireland. Emerging Infectious Diseases 2005; 11:590-6.