The management of VTEC O157 infection

VTEC O157 infections, although showing a relentless rise in incidence over the last decade, only account for less than 10% of total food poisoning notifications in the UK. Despite this, the propensity for this infection to cause the serious and life-threatening clinical complications of haemolytic uraemic syndrome (HUS) and thrombotic thrombocytopaenic purpura (TTP), in a significant proportion (2-15%) of sufferers, highlights the need to focus on it both epidemiologically and clinically. The mortality rate of these complications (3-17% and up to 30% in outbreaks) adds urgency to this consideration. The pathogenesis and epidemiology of the illness caused by VTEC O157 is now well described, allowing the potential for appropriate intervention in outbreak and individual clinical management. The presence or absence of symptoms, e.g. bloody diarrhoea, fever, vomiting, in VTEC O157 infections compared with other causes of gastroenteritis may allow some selection of cases for more intensive management. Age (< 15, > 65 years), clinical hypochlorhydria. and a short incubation period have been associated with complication (HUS/TTP) development. Antibiotic therapy in the pre-infection period may predispose to complication development and there is evidence that it may increase complications if used in the management of acute illness. Laboratory markers such as early neutrophil leukocytosis have been shown both to correlate with VTEC O157 infection and to predict complications in central Scotland and Japan. The serum albumin and the C-reactive protein may act as additional markers for HUS development. Laboratory markers may be differentiated into those predicting HUS/TTP and those useful in monitoring its development. A scheme for clinical management of affected cases is presented to allow the attending clinician to select cases that may benefit from further intervention to prevent or treat complications.