VOL: 101, ISSUE: 41, PAGE NO: 25- Verocytotoxin-producing Escherichia coli (VTEC) is a strain of E. coli bacteria that produces potent toxins....
WHAT IS IT?
- Verocytotoxin-producing Escherichia coli (VTEC) is a strain of E. coli bacteria that produces potent toxins.
- The most important one associated with human disease is O157 (VTEC O157).
- The fatality rate of VTEC O157 infections is very variable and depends on the ages of the groups affected. Rates from one to five per cent have been reported.
- Laboratory isolations of E. coli 0157 in the UK have risen steadily from less than 10 each year in the early 1980s to 656 in 1994 and 1,039 in 1995 (Association of Medical Microbiologists, 2005).
- Most infections are diagnosed in children under five and the majority of cases occur in the summer and early autumn.
- The true incidence is probably much higher as many patients with diarrhoea do not have laboratory investigations.
- Mild diarrhoea.
- Haemorrhagic colitis with frank bloody diarrhoea and severe abdominal cramps, normally without fever, in up to 10 per cent of patients.
- Haemolytic uraemic syndrome (HUS), involving acute renal failure, haemolytic anaemia and thrombocytopaenia can develop.
- Some patients, usually adults, develop thrombotic thrombocytopenic purpura (TTP) in which the clinical features of HUS are seen together with neurological complications.
- Symptoms usually resolve within two weeks, except in cases of HUS or TTP.
- Asymptomatic carriage has been reported.
- A very small number of bacteria - fewer than 100 organisms - are needed to cause an infection.
- Transmission occurs as a result of consumption of contaminated foods, particularly inadequately cooked minced beef, beefburgers and milk.
- Consumption of contaminated yoghurt, cooked meats, meat pies, cheese, dry-cured salami, raw vegetables, unpasteurised apple juice and water have also been responsible for infections.
- Outbreaks due to person-to-person infection have occurred within households, nurseries and infant schools.
- The incubation period can range from 1-14 days, with a median of 3-4 days.
- Infections are usually self-limiting. Simple measures such as plenty of fluids, a light diet and rest are normal management.
- Benefits of antibiotic treatment have yet to be established.
- Close attention to infection control and personal hygiene is important.
- If HUS, TTP or renal failure develop, they are treated by conventional means.
- All cases should be reported to a consultant for communicable disease control or equivalent.