Clinical presentation

Prompt recognition and appropriate management of Escherichia coli O157 (E. coli O157) and other Shiga toxin-producing E. coli (STEC) infections are crucial to reduce morbidity and mortality, especially in vulnerable populations such as children and the elderly. Around 40% of patients diagnosed with STEC need to be admitted to hospital.¹ 

Urgent discussion of clinically suspected cases with the local public health team is needed to reduce the risk of person-to-person spread and large outbreaks.

Incubation period

The incubation period for STEC infection is usually three to four days, with a range of one to ten days. However, longer incubation periods have been reported.^6,14,15,16

Clinical presentation

STEC infections can present as a spectrum of illness, ranging from asymptomatic to severe disease. Common symptoms include:

• diarrhoea, which may be mild non-bloody or bloody

• abdominal pain

• fever and vomiting.

A severe complication of STEC infection is haemolytic uremic syndrome (HUS).²

Heamolytic Uremic Syndrome

Mortality from STEC infection is largely associated with HUS and its renal and neurological complications. HUS is characterised by:

• microangiopathic haemolytic anaemia

• thrombocytopenia

• acute kidney injury.

Incidence

• 10-15% of people with STEC infection will develop HUS³

• children under 15 years and older adults are more likely to develop HUS, particularly children under 5 years and adults over 65 years^4,5

Clinical features associated with more severe illness and increased risk of HUS include:^{1,2,3,4,6,7,8,9,10,11,12}

• dehydration

• frequent bloody stools

• severe abdominal pain or cramps

• vomiting

• pallor

• petechiae

• oliguria

• blood and protein on urine dipstick.

Laboratory indicators of established HUS include:

• anaemia (dehydration with subsequent haemoconcentration may obscure anaemia)

• fragmented red cells on blood film

• thrombocytopenia

• rising urea and creatinine

• elevated low-density lipoprotein.