E.coli O157 & Haemolytic Uraemic Syndrome

Understanding E.coli O157

What is E.Coli?

It is a bacterium commonly found in the intestines of man and animals. We need this bacteria to break down cellulose and it assists in the absorption of vitamin K, the blood-clotting vitamin.

E.coli O157 is a strain which lives in the intestines of some cattle, sheep and goats but is not naturally found in the intestines of man. It produces toxins which can be potentially fatal when ingested in very small amounts e.g. (by ingesting as few as 10 E.coli O157 organisms a person can develop symptoms, yet up to 1 million salmonella organisms can be ingested before symptoms will present).

Since first being identified as a human health risk in 1982 the number of cases has been rising significantly each year. It was initially known as the “hamburger bug” due to the number of outbreaks resulting from eating undercooked hamburgers. However in recent years microbiologists have discovered that a significant amount of these cases can be as a result of environmental causes – i.e. from playing in fields once occupied by cattle and sheep or by touching infected animals

What harm can E.Coli O157 do to humans?

Normally the most vulnerable groups are children, the elderly or those who suffer from suppressed immune systems. Initially symptoms can present as diarrhoea (often bloody), severe abdominal pain and sickness. In a small percentage of cases sufferers can go on to develop HUS (Haemolytic Uraemic Syndrome) which can lead to kidney failure and is sometimes fatal.

Some people, particularly the elderly, may develop TTP (Thrombotic Thrombocytopaenic Purpura) which can result in an encephalitis-like disease, with psychosis, comas or seizures


Antibiotics should not be used as it has been proven that these can increase the risk of developing HUS. In addition, certain types of products that can be bought over the counter from chemists and used for diarrhoea type illnesses have also been shown to increase the chances of E.coli O157 developing into HUS.

Can I catch it from someone else? (Person-to-Person)

Great care must be taken if someone is infected. The infected person may have been given advice by their GP/Environmental Health Officer/Communicable Disease Personnel, which will ensure their levels of personal hygiene are high. As the bacterium is excreted in bowel movements cross-contamination cannot occur by person-to-person contact unless they are not practicing high levels of hygiene. The charity realises the difficulty of this, particularly with young children. Several cases of person-to-person cross contamination have occured, even by health professionals caring for sufferers.

How does cross-contamination occur? (Food-to-Food)

Cross-contamination of food can occur if the same utensils are used for preparing uncooked meat and other food.

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