Topic: Shiga toxin-producing E. coli (STEC)
Description
Escherichia coli (E. coli) are bacteria which are present in large numbers in the intestines of humans and animals. Most of these bacteria are not harmful. However, some strains, such as Shiga toxin-producing E. coli (STEC), produce toxins which can cause a range of illness in humans and may lead to serious complications in the bowel and kidney. Meat from infected animals can be contaminated during slaughter and processing, particularly if minced. Unpasteurised milk, contaminated raw vegetables and contaminated water are also potential sources of infection.
Symptoms
Symptoms of infection include abdominal pain and watery or bloody diarrhoea. Vomiting and fever may occur. Symptoms can begin anywhere between 2 to 10 days but usually 3 – 4 days after eating the bacteria. Infection may sometimes cause no or very mild symptoms.
Transmission
The infection is mainly spread through people eating contaminated food. It can also spread from person to person if hands are not washed thoroughly after going to the toilet or changing nappies. People infected and their close household contacts should consult a doctor before returning to work or school. Adults are generally infectious for one week or less but one third of children remain infectious for around three weeks. People can occasionally remain infectious for considerably longer.
Treatment
Most people with mild illness recover without any specific treatment. Occasionally complications such as dehydration and kidney failure may require hospitalisation, sometimes in intensive care. The role of antibiotics in the management of STEC is unclear. Antibiotics are generally not recommended as they may increase the risk of haemolytic uraemic syndrome (see below).
Health Outcome
Most people with STEC infection recover fully. Occasionally, people with this infection can go on to develop a condition called haemolytic uraemic syndrome (HUS). The risk of HUS following STEC infection has been estimated to be up to 8%. The elderly and children are at highest risk. HUS develops between 2 and 14 days after the onset of diarrhoea and is characterised by kidney failure and anaemia. It can sometimes be fatal.
Prevention
Cook meat, including minced meat, eg. hamburgers, thoroughly until the juices run clear and there are no pink areas inside. Do not serve unpasteurised milk and its products. Wash raw fruit and vegetables thoroughly before eating.
Always wash your hands after going to the toilet, changing nappies, before and after handling food and before eating. Thorough hand washing with soap and water is the key to preventing the spread of this infection. Good hygiene practices are necessary when suspected or diagnosed cases of this infection are being cared for. The sick room, toilet and kitchen are high risk areas. Surfaces in these areas should be cleaned regularly with detergent and hot water.
The risk of spreading infection is higher among the following groups:
- food handlers in the home, in institutions or in industry, especially those handling raw or uncooked foods
- carers of vulnerable people eg. nurses and doctors and childcare centre staff
- children under five years of age who attend childcare
- people who have difficulties in practising good personal hygiene.
Help and Assistance
For further information please contact your local doctor, community health centre or nearest population health unit.
Footnotes
Heymann D (Ed). 2008. Control of Communicable Diseases Manual, 19th edition. Washington, DC: American Public Health Association, pp 181-186.
Ochoa TJ, Cleary TG. Epidemiology and spectrum of disease of Escherichia coli O157. Curr Opin Infect Dis 2003, 16:259-63.
Thorpe C. Shiga toxin-producing Escherichia coli infection. CID. 2004, 38:1298-303.
Other Resources
- Queensland Health Food Safety Matters website
Last Updated: 4th October, 2010
Date Valid to: 29th September, 2011
