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Home Topics Infectious Diseases Infections A-Z Vero cytotoxin-producing Escherichia coli (VTEC)
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Vero cytotoxin-producing Escherichia coli (VTEC)

E coli image

Escherichia coli (E. coli) are common bacteria which live in the intestines of warm blooded animals. There are certain forms (strains) of E. coli which are normally found in the intestine of healthy people and animals without causing any ill effects, however some strains are known to cause illness in people. Among these is a group of bacteria which are known as Vero cytotoxin-producing E. coli or VTEC*.

These can cause illness, ranging from mild through severe bloody diarrhoea, mostly without fever, to two serious conditions known as haemolytic uraemic syndrome (HUS) and thrombotic thrombocytopaenic purpura (TTP) that affect the blood, kidneys and in severe cases the central nervous system. The most important property of these strains is the production of one or more potent toxins important in the development of illness. VTEC are relatively rare as the cause of infectious gastroenteritis in England and Wales; however the disease can be fatal, particularly In infants, young children and the elderly.

The most important VTEC strain to cause illness in the UK is E. coli O157, which will be referred to below as VTEC O157. This can be found in the intestine of healthy cattle, sheep, goats and a wide range of other species. Humans may be infected by VTEC O157 or other VTEC strains when they consume food or water that has become contaminated by faeces from infected animals. Infection may also result from direct or indirect contact with animals that carry VTEC or from exposure to an environment contaminated with animals faeces, such as farms and similar premises with animals which are open to the public. In these cases the bacteria are transferred from contaminated material to the mouth when proper hand hygiene advice is not followed. The infectious dose of VTEC O157 is very low at less than 100 bacterial cells. Infection is readily spread between family contacts, particularly those who may be caring for infected children, and in settings such as children’s day nurseries.

The Health Protection Agency undertakes epidemiological investigations and provides advice for the control of VTEC outbreaks. We confirm and type strains by a range of methods so that strains from cases can be compared with those isolated from suspect foods and other type specimens collected during outbreak investigations. We also look for any patterns or trends which can show possible connections between the people who are infected. When a case is found, health protection specialists in Health Protection Units across the country work with environmental health officers to find out how people became ill and thus to prevent other people from becoming infected by giving advice to the families of cases and sometimes having food products removed from the market. Where outbreaks are linked to contact with animals or their environment, we work closely with the Veterinary Laboratories Agency (VLA) to investigate the source, with the provision of additional advice about animal-related aspects.

*VTEC refers to both Vero cytotoxin-producing Escherichia coli and Verotoxigenic Escherichia coli - they are the same. Shiga-toxin-producing Escherichia coli (STEC) is synonymous with VTEC. Enterohemorrhagic Escherichia coli (EHEC) is a subgroup of these.