| 17 October 2008 |
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E coli O157: H7
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Causative agent
E. Coli O157:H7 is a strain of Escherichia coli, bacteria that usually found in the intestines of warm-blooded mammals, like cattle. This E. coli strain can produce a powerful toxin and may cause severe gut symptoms, like bloody diarrhoea.
Clinical features
Victims may develop symptoms that include severe watery diarrhoea, bloody diarrhoea, fever, abdominal cramps and vomiting. In serious cases, it may be complicated by acute kidney problems. Children under five have a higher risk of such complications. If not properly treated, the infection may cause death.
Mode of transmission
The infection is contracted through consumption of contaminated water or undercooked contaminated food, especially minced beef, hamburgers and roast beef. Cases due to consumption of raw milk, cheese, vegetables, fruit juices and yogurt have been reported. Moreover, if personal hygiene is poor, person-to-person transmission of these bacteria is possible through faecal-oral route.
Incubation period
Usually 3 to 4 days but can be up to 9 days.
Management
The clinical management for E coli O157:H7 infection is essentially supportive. Fluid and electrolyte replacement is important when there is watery diarrhoea. About 50% of patients with kidney complications require specific support and transfusion in the acute stage.
Prevention
1. Keep the premises and kitchen utensils clean. Dispose rubbish properly.
2. Keep hands clean and fingernails trimmed.
3. Wash hands properly with soap and water before eating or handling food, and after toilet or changing of diapers.
4. Drinking water should be from the mains and preferably boiled.
5. Purchase fresh food from reliable sources. Do not patronize illegal hawkers.
6. Avoid high-risk food, like unpasteurized milk, undercooked hamburgers, ground beef and other meat products.
7. Wear clean washable aprons and caps during food preparation.
8. Clean and wash food thoroughly.
9. Store perishable food in refrigerator, well covered.
10. Handle and store raw and cooked food especially beef and cattle offal separately (upper compartment of the refrigerator for cooked food and lower compartment for raw food) to avoid cross contamination.
11. Clean and defrost refrigerator regularly and keep the temperature at or below 4oC.
12. Since E. coli O157:H7 can be killed if all parts of the food reach 75oC, cook all ground beef and hamburger thoroughly to 75oC for 2 to 3 minutes, until the cooked meat is brown throughout and the juices run clear.
13. Do not handle cooked food with bare hands; wear gloves if necessary.
14. Consume food as soon as it is done.
15. If necessary, refrigerate cooked leftover food and consume as soon as possible. Reheat thoroughly before consuming. Discard any addled food items.
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