ESCHERICHIA COLI Introduction Escherichia coli 0157:H7 (E. coli 0157) is a cause of food borne illness. Infection may result in sickness and diarrhoea, which can often be severe and with blood. Complications may arise, such as kidney failure due to the poisons produced by the bacteria. Most cases of illness have been associated with eating undercooked, contaminated ground beef, cooked-chilled foods and salads. E. coli 0157:H7 can be prevented by heating thoroughly all cooked foods, not drinking unpasteurised milk and following normal good hygiene practices, such as cleaning and disinfecting all kitchen work surfaces properly and storing foods in the refrigerator to ensure raw foods don t contaminate foods ready to eat. What is Escherichia coli? Many different strains of E. coli are found naturally in all animal species, including humans, and in the soil as a result of faecal contamination. It is common for many foods, e.g. raw meat and unwashed vegetables, to be contaminated accidentally. There is no way of knowing if and when this contamination may have taken place. Suffice it to say that the main events follow poor kitchen and food handling process. However, unlike the majority of E. coli strains which are harmless, E. coli 0157 can produce a powerful toxin during its multiplication phase within the intestine and as a result it can cause severe illness, which may be lifethreatening. The E. coli bacterium is one of 500 different types of bacteria within the normal intestine of humans. Each gram of faeces contains 100 trillion bacteria, that s ten times more than all the functional cells within the human body! Due to the virulence of the 0157 strain, even normal inhabitants can be overwhelmed and ousted. Pet Health Council Escherichia coli Updated November 2004 1
Infections in Animals E. coli 0157 may be cultured from time to time in the faeces of all animal species. In most cases their presence does not cause a problem for the animal; the animal is then called a carrier. Like humans, where there is a problem it will cause diarrhoea, debility and death in some cases. Escherichia coli and Humans Meat can become contaminated following slaughter. Most of the contamination is on the surface so that thorough cooking of the outside is usually effective in killing the organism. It is very susceptible to heat, disinfectants and radiation. When meat is prepared, as in the production of hamburgers or minced meat, then surface contamination can be driven into the centre. Hence the need to ensure all prepared meat is properly cooked to the centre. Drinking raw unpasteurised milk is not recommended. Since cow s, goat s and ewe s udders are close to their anuses and soiled backsides it is an easy step for the E. coli to get into the milk, despite the most obsessional udder and teat cleansings. Although the exact number of organisms required to cause the disease in humans is not known, it is suspected the number is small. They multiply rapidly in the intestine within hours and give rise to the common signs called food poisoning. Symptoms may appear within a few hours up to 36 hours or more following ingestion. The first signs may be nausea and stomach pains. Fever and collapse may accompany the eventual sickness and diarrhoea. Other sources of infection result from poor hygienic practices. Since faeces are the source, the failure to wash hands after going to the toilet or handling contaminated foodstuffs and kitchen utensils is an easy way the organism makes its way to the next subject. Contracting the disease is not an animal s fault but due to human negligence. Pet Health Council Escherichia coli Updated November 2004 2
Even bacteria in the stools of infected people can be passed from one to another if hygiene or hand-washing habits are inadequate. Children, the elderly and those with compromised immune systems are particularly susceptible to the disease. When dealing with these people scrupulous care must be exercised to avoid transmission through unwashed hands, utensils or foods. Young children typically shed the organism in their stools for a week or two after their illness resolves. Children rarely carry the organism without symptoms. Because of the risk of transfer of the bacteria from contaminated meat, it is highly advisable that raw meats are not fed to pets. Diagnosis Infection with E. coli 0157:H7 is diagnosed by detecting the bacterium in the stool. All persons who suddenly have severe bloody diarrhoea should get their stools tested in a laboratory for E. coli 0157:H7 and other common contagions. A medical practitioner should be consulted if any of the symptoms detailed above are experienced, particularly when having been abroad, having eaten out or if another family member has shown signs. Human Treatment Most people recover in five to ten days with home care, specific intestinal medications and fluids by mouth without the need for antibiotics or other specific treatment. There is insufficient evidence that antibiotics improve the course of the disease in the majority of cases, although in extreme conditions they may be needed to avoid further complications. Fluid replacement is always indicated, but under strict supervision. Prevention of E. coli in Animals E. coli is found naturally in all animal species. There are, in normal animal husbandry, no easy preventive measures that can be taken to avoid an animal becoming infected with E. coli 0157. Prevention of E. coli in Humans All ground beef and hamburgers should be cooked thoroughly to the centre so that the meat is grey without any pinkness. Avoid spreading harmful bacteria Pet Health Council Escherichia coli Updated November 2004 3
in your kitchen; keep raw meat separate from ready-to-eat foods, i.e. at the bottom of the fridge. After touching raw meat, wash hands in hot soapy water and clean counters and utensils after they have been used in food preparation with antibacterial products. Wash fruits and vegetables thoroughly, particularly those that will remain raw. Make sure that persons with diarrhoea, especially children, wash their hands carefully with soap and water after bowel movements to reduce the risk of spreading infection, and likewise that people wash their hands after changing dirty nappies. Conclusion People can prevent E. coli 0157:H7 infection in humans by thoroughly cooking ground meats, avoiding unpasteurised milk, by strict kitchen hygiene and washing hands carefully. The PHC recommends that pet and non-pet owners keep this issue in perspective and that a sensible hygiene routine should always be followed: Always wash hands after handling pets and after gardening (ideally wear gloves that can be washed) Keep pets away from food preparation areas and equipment Ensure your pet follows a preventative health routine with regular visits to the vet Clear up after your pet Thoroughly wash fruit and vegetables before eating Thoroughly cook all raw meats Adopt strict hygienic measures in the kitchen Avoid unpasteurised milks Drink properly sterilised water Be careful and watchful when eating out, where food hygiene standards are not assured Pet Health Council Escherichia coli Updated November 2004 4
Remember that E. coli 0157 is only caught by humans because faeces and food have been mixed! Pets are Good for People Pets provide us with loyalty, companionship, love and affection, as well as the many physical and psychological benefits. The least we can do to repay this is to ensure that we keep them in the best of health. A healthy pet is a happy pet and a happy pet can help us enjoy a much fuller and more rewarding life. - ends - For further information, please contact the Pet Health Council on: Telephone: 020 7379 6545 Email: enquiries@pethealthcouncil.co.uk Website: www.pethealthcouncil.co.uk Pet Health Council Escherichia coli Updated November 2004 5