What is it?

E-coli 0157 is one of hundreds of strains of the bacterium Escherichia coli. Although most strains are harmless and live in the intestines of healthy humans and animals, this strain produces a powerful toxin and can cause severe illness.

How do I know if someone has it?

E-coli 0157 infection often causes severe bloody diarrhoea and abdominal cramps; sometimes the infection causes non-bloody diarrhoea or no symptoms. Usually little or no fever is present, and the illness usually resolves in 5 – 10 days. In some persons, particularly children under 5 years of age and the elderly, the infection can also cause a complication called haemolytic uraemic syndrome, in which the red blood cells are destroyed and the kidneys fail. About 2% - 7% of infections lead to this complication. Haemolytic uraemic syndrome is a principal cause of acute renal failure in children, and most cases of haemolytic uraemic syndrome are caused by E-coli 0157.

Is it infectious?

The organism can be found on a small number of cattle farms and can live in the intestines of healthy cattle. Meat can become contaminated during slaughter, and organisms can be thoroughly mixed into beef when it is ground. Bacteria present on cows’ udders may get into raw milk. Eating meat, especially ground beef (beef burgers), that has not been cooked properly can cause infection. Among other known sources of infection are consumption of sprouts, lettuce, salami, unpasteurised fruit juice, raw milk and swimming in or drinking water contaminated with sewage. Bacteria in diarrhoeal stools of infected persons can be passed from person to person if hygiene or hand washing habits are inadequate. This is particularly likely among toddlers who are not toilet trained. Family members and playmates of these children are at high risk of becoming infected. Young children typically shed the organism in their faeces for a week or two after their illness resolves. Older children rarely carry the organism without symptoms.

What is the incubation period?

Symptoms usually begin 3 - 8 days after eating contaminated food.

What should I do if someone has the illness?

Most people will get better without antibiotics or other specific treatment in 5 – 10 days. There is no evidence that antibiotics improve the course of the disease. Anti-diarrhoeal agents, such as loperamide (Imodium) should also be avoided. Haemolytic uraemic syndrome is a life-threatening condition usually treated in an intensive care unit. Blood transfusions and kidney dialysis are often required.

How can spread be avoided?

• Cook all meat thoroughly.
• Avoid spreading harmful bacteria in your kitchen. Keep raw meat separate from cooked foods. Store raw meats on the bottom shelf of the fridge.
• Wash hands, work surfaces and utensils with hot soapy water after they come in contact with raw meat.
• Drink pasteurised milk, fruit juice or cider.
• Wash fruits and vegetables thoroughly, especially those which are to be eaten raw.
• Drink only treated tap water.
• Ensure that anyone with diarrhoea, especially children, washes their hands after visiting the toilet to reduce the risk of spreading the infection.
• Make sure that hands are thoroughly washed after changing soiled nappies.
• Never place cooked meat onto an unwashed plate which held raw meat.
• Anyone with diarrhoea should avoid swimming in public pools or lakes, sharing baths with others, and preparing foods for others.

How soon can someone return to school/work?

Cases not in the risk groups below should be excluded from work until they have been free of symptoms for 48 hours.

Risk groups have been identified as:

• Food handlers whose work involves touching equipment used to prepare food in kitchens or unwrapped foods to be consumed raw or without further cooking.
• Health care staff, who have direct contact, or contact through food, with people in whom infection may be severe.
• Children under the age of 5 who attend nurseries, playgroups or other similar groups.
  People with poor hygiene or living in poor accommodation, e.g. People with learning difficulties and elderly infirm.

Cases in the above risk groups and contacts of children under 5 and people with poor hygiene should be excluded until microbiological clearance is obtained ie two negative stool cultures taken at intervals of not less than 48 hours.

For further information the websites below may be of interest.

Date Published: 28/03/08