Escherichia coli O104: understanding the risks and preventing the spread of infection

June 2011

This leaflet has been put together to provide background information and advice on what to do if there is a risk of spread of E. coli O104. This briefing material has been produced for those who work in the healthcare professions, the media and others who are looking for some background understanding of hygiene issues related to E. coli O104 and/or those who are responsible for providing guidance to the public on coping with hygiene issues associated with E. coli O104.

On 21st May 2011, Germany reported an ongoing outbreak of Shiga-toxin producing Escherichia coli (STEC), serotype O104:H4. This strain of E. coli had previously not been associated with significant health problems in the EU and seems to have a different epidemiology than disease-causing strains of STEC so far identified in the EU such as E. coli O157. The strain of E. coli O104 currently circulating in Europe is thought to be new and is proving to be particularly dangerous. The strain of E. coli O104 which is currently circulating in Europe is an enteroaggregative hemorrhagic strain of E. coli which produces high toxin concentrations. It is thought to be a new strain and is proving particularly very dangerous.

In Germany, over 3304 cases have been reported and 38 deaths (by June 16th 2011). The outbreak has spread in only a very limited way in the rest of Europe, causing 91 confirmed cases and a single death. These have largely been in people who had recently travelled from Germany. In total, in the EU/EEA, 3407 cases including 39 deaths have so far been recorded.

German authorities conclude, based on epidemiological evidence, that sprouts (either bean, alfalfa, fenugreek or other (but not brussels sprouts)) are likely to be the cause of the outbreak, coming from one market garden in Lower Saxony. Sprouts eaten by a person who developed the disease from this market has now tested positive. Therefore there is now also microbiological evidence for this thesis. In the meantime there are secondary infections from person to person contact. At present, it is unclear how the produce became contaminated, but it may be the result of contaminated water for irrigation of the sprouts, direct contact from infected persons producing the sprouts or animal manure products being used as fertilisers.

Health Agencies are advising that anyone returning from Germany with illness including bloody diarrhoea should seek urgent medical attention and make sure they mention their recent travel history. People who are travelling to Germany should follow the advice of the authorities and avoid eating all types of sprouts until further notice. Although Shiga-toxin producing strains of E. coli are not highly contagious, by comparison, for example, with cold, flu and enteric (norovirus) viruses, infection can be transmitted from an infected person to others with whom they come into close contact.

What is E. coli O104?

All humans and animals carry the bacteria called Escherichia coli (E. coli) in their intestines – they are part of our normal flora and usually harmless.1 However, there are particular strains of E. coli that are capable of producing toxins. These strains are called STEC/VTEC (shiga toxin or verotoxin-producing E. coli) or EHEC (enterohaemorrhagic E. coli), and their toxins have the potential to cause severe, bloody diarrhoea, which may in some cases result in an acute kidney failure requiring intensive care. The strain involved in the German outbreak has caused cases of haemolytic uraemic syndrome (HUS). HUS is a serious complication caused when bacteria produce a toxic substance called verocytotoxin. This can affect the blood, kidneys and, in some cases, the nervous system. It requires hospital treatment and, although most people make a full recovery, it can be fatal. While HUS cases are usually observed in children under 5 years of age, over 85% are adults in this outbreak, with a clear predominance of women (about 70%).

Usually, people have diarrhoea that settles within seven days without treatment. For general food poisoning (from any type of bacteria), you should see a doctor if:

 Vomiting lasts for more than two days  It is not possible to keep liquids down for more than a day  Diarrhoea lasts for more than three days  There is blood in your vomit or stools  You experience seizures, fits, slurred speech or double vision  You are dehydrated (symptoms include dry mouth, sunken eyes and being unable to pass urine).

How do people become infected?

E. coli enters the body to infect the gastrointestinal tract via the mouth. It gets into the mouth via contaminated food or hands and sometimes via water (although water contamination is unusual in the UK).

1 E. coli is one of the group of species which are referred to as “faecal coliforms” because they are commonly found in the gut – and therefore in faeces. The isolation of “faecal coliforms” from an environmental surface etc is commonly used as an “indicator” that the surface is contaminated with material of faecal origin and/or of poor hygiene. This does not necessarily mean that the organisms are pathogenic strains of E. coli. This can only be determined by further identification tests.

Page 2/7 There are four routes through which humans can become exposed and potentially infected:

FOODBORNE WATERBORNE ANIMAL PERSON TO CONTACT PERSON  Contaminated  Contaminated  Direct or  faecal:oral route products of water supply indirect contact animal origin with animals (meat etc.) and their  - Contaminated faeces fruit and vegetables

HUMAN EXPOSURE

German authorities conclude that sprouts are likely to be behind the outbreak coming from one market garden. At present, it is unclear how the produce became contaminated, but it may be the result of contaminated water for irrigation of the sprouts, direct contact from infected persons producing the sprouts or animal manure products being used as fertilisers.

Some studies have shown that STEC strains can survive for several weeks on plants. Survival of STEC E. coli O157 has been demonstrated for 177 days when sprayed directly onto parsley, and for 30 days on lettuce. However, these studies were typically conducted with highly contaminated plants, which may not be consistent with what would occur in a natural soil contamination scenario. In contrast, survival for only a few days after irrigation of spinach with water containing a high number of STEC O157 was reported, and where contamination was low, STEC O157 was no longer detected 24h after irrigation.

Once the source of the current outbreak of E. coli O104 has been isolated and destroyed, there will no longer be a risk of becoming infected by consumption of the original batch of sprouts. Until that time, the public should follow the advice given by national food/health authorities about what foods they should avoid eating. Any potential risk is from uncooked vegetables; thorough cooking of vegetables destroys the bacteria and makes food safe to eat.

For anyone who has not travelled recently to Germany, there is very little risk. For anyone returning from Germany who is infected or thinks they might be infected, it is important to make sure they do not infect other family members or contacts. This means good hygiene – the same as for any stomach bug. At least one case of intrafamilial transmission has been reported in Germany. Person-to-person contact in families, nurseries, infant schools etc. is a known mode of transmission of STEC strains of E. coli. Bacteria in diarrhoeal stools of infected persons can be passed from one person to another if hygiene or hand washing habits are inadequate. Studies on E. coli O157 show that they can be transmitted in the home to cause secondary

Page 3/7 infections because their infectious dose is very low (maybe as few as 10). In a study carried out in Wales, secondary transmission from an infected person to another family member in the home is estimated at 4–14%.

Although the primary human infections in this outbreak have originated from consumption of contaminated sprouts, secondary infection can occur by contamination of food through handling by an infected person shedding the bacteria. Secondary cases can also occur by hand to mouth contact after touching surfaces that are contaminated e.g. the toilet seat or flush handle. As a result, especially during the late stages of an outbreak multiple exposure routes are possible.

Preventing the spread of E. coli O104 infection in the home In situations where there is risk of spread of E. coli O104 infection in the home from an infected person, the following hygiene measures should be rigorously implemented. It must be remembered that E. coli O104 can also be shed by people who have no symptoms – both those who have apparently recovered and those who have not developed symptoms.

 Food can be contaminated with E. coli O104 because it has been contaminated by handling with contaminated hands or being placed on a contaminated surface.  Hands can be contaminated in a whole variety of ways such as visiting the toilet, handling contaminated food or touching a surface which has been touched by someone else with contaminated hands. Infection can occur by touching the mouth with contaminated hands.

General Hygiene To prevent transmission of infection from an infected family member (or a family member who may have been exposed to infection outside the home) to other family members or to food:

 Good hand washing practice is the single most important infection control measure. Hands should be thoroughly washed with soap and running water*. If access to soap and running water is a problem, use an alcohol hand rub or hand sanitiser. In “high risk” situations where there is an outbreak of E. coli O104 in the home, it is suggested that hand washing followed by use of an alcohol rub/sanitiser should be encouraged. All family members should ensure that hands are washed: - After using the toilet or changing a baby’s nappy - Before preparing, serving or eating food (see also instructions for handwashing as part of food and kitchen hygiene) - After taking care of the infected person - After carrying out the cleaning practices as described below.  Hygienically clean surfaces in the bathroom and toilet, with particular attention to washbasins, baths and toilet seat and toilet handles. This can be achieved by cleaning with a detergent cleaner followed by thorough rinsing under running water, or when this is not possible, e.g. for toilet seats, toilet flush handles, by use of a disinfectant cleaner. If someone has diarrhoea, toilets should be disinfected after each use.  Keep the infected person’s immediate environment hygienically clean. The most important surfaces are those which come into contact with the hands, e.g. door handles, telephones, bedside tables and bed frames. To make these surfaces hygienically clean you need to use a disinfectant product. In a busy household it Page 4/7 is not always possible to keep hand contact surfaces hygienically clean at all times. This is why it is so important to wash hands as frequently as possible to break the chain of infection.  Cleaning cloths can easily spread E. coli infection around the home. They should be hygienically cleaned after each use, particularly after use in the immediate area of the infected person or the bathroom and toilet used by that person. This can be done in any of the following ways: - Wash in a washing machine at 60°C (hot wash) - Clean with detergent and warm water, rinse and then immerse in disinfectant solution which is effective against E.coli O104 for at least 20 minutes or as prescribed - Clean with detergent and water then immerse in boiling water for 20 minutes - Alternatively, use disposable cloths.  Where floors or other surfaces become contaminated with faeces or vomit, they should be hygienically cleaned at once: - Remove as much as possible of the excreta from the surface using paper or a disposable cloth, then apply disinfectant cleaner** which is effective against E. coli O104 to the surface using a fresh cloth or paper towel to remove residual dirt - Apply disinfectant cleaner** to the surface a second time using a fresh cloth or paper towel to destroy any residual contamination.  Disposable gloves should be worn if in contact with faeces, and hands should be washed after removing gloves.  Clothing, sheets, pillows and linens from the infected person (or carrier) should be kept separate from the rest of the family laundry and should be laundered in a manner which kills any E. coli O104. Either: - For preference, wash at 60°C or above using any laundry product as heat will destroy E. coli O104 Or - Wash at 40°C using a bleach-containing laundry (powder or tablet) product.

Note: washing at 40°C without the addition of bleach will not destroy E. coli O104.

 Do not share towels, facecloths, toothbrushes and other personal hygiene items with the infected or carrier person.  Where young children are ill, or at particular risk: - Their hand washing, personal and toilet hygiene may need supervision - Nappies should be disposed of safely, or cleaned, disinfected and washed. Contrary to popular perception, the faeces of babies can be highly infectious.  Where possible, infected individuals should stay in their own room and use their own facilities, cutlery, crockery etc. Infected people should particularly avoid contact with those who may be more vulnerable to infection, and their personal items.

Food and Kitchen hygiene

Page 5/7 Rigorous food hygiene is important in preventing the spread of E. coli O104. Where there is an infected or suspected infected person in the home, food hygiene practices should focus on preventing contamination of food, particularly ready-to-eat foods. Where there is a suspected contaminated food source of E. coli O104 in the home, food hygiene practice should focus on containing and destroying the source, and preventing transfer to other foods:  Infected people should try to stay away from the kitchen and should not prepare food for others  Wash hands after handling food which may be contaminated and disinfect using an alcohol handrub or sanitiser  Wash hands before handling ready to eat foods and disinfect using an alcohol handrub or sanitiser  Hygienically clean all food contact surfaces, utensils and cloths after handling and preparation of raw foods using a disinfectant cleaner which is effective against E. coli O104**. Hygienically clean all contact surfaces, utensils and cloths before handling and/or preparing ready to eat foods  Cook foods thoroughly  Wash any foods such as fruit and vegetables to be eaten raw thoroughly under clean running water  Store foods carefully in a refrigerator or freezer. Ensure that raw foods are kept separate from cooked foods.

*How to wash hands: Hand washing “technique” is very important. Rubbing with soap and water lifts the germs off the hands, but rinsing under running water is also vital, because it is this process which actually removes the germs from the hands. The accepted procedure for hand washing is:

 Ensure a supply of liquid soap, warm running water, clean hand towel/disposable paper towels and a foot-operated pedal bin  Always wash hands under warm running water  Apply soap  Rub hands together for 15–30 seconds, paying particular attention to fingertips, thumbs and between the fingers  Rinse well and dry thoroughly.

In situations where soap and running water is not available, an alcohol-based hand rub or hand sanitiser should be used to achieve hand hygiene:

 Apply product to the palm of one hand  Rub hands together  Rub the product over all surfaces of hands and fingers until your hands are dry.

Note: the volume needed to reduce the number of germs on hands varies by product. In high-risk situations where there is an outbreak in the home, hand washing followed by use of an alcohol rub/sanitiser should be encouraged.

One very simple thing that people can do to reduce the risk of disease is to avoid putting their fingers to their mouth.

**Disinfectants and disinfectant cleaners

Page 6/7 Make sure you use a disinfectant or disinfectant/cleaner such as a bleach-based product, which is active against E. coli O104. For more details on choosing the appropriate disinfectant, see the IFH information sheet “Cleaning and disinfection: Chemical Disinfectants Explained”. Consult the manufacturers’ instructions for information on the “spectrum of action”, and method of use (dilution, contact time etc.). For bleach (hypochlorite) products, use a solution of bleach, diluted to 0.5% w/v or 5000 ppm available chlorine. Household bleach (both thick and thin bleach) for domestic use typically contains 4.5 to 5.0% w/v (45,000–50,000 ppm) available chlorine. In situations where “concentrated bleach” is recommended a solution containing not less than 4.5% w/v available chlorine should be used. Bleach/cleaner formulations (e.g. sprays) are formulated to be used “neat” (i.e. without dilution). It is always advisable, however, to check the label as concentrations and directions for use can vary from one formulation to another.

Other “facts about” sheets giving information on E. coli O104 1. Public health advice on prevention of diarrhoeal illness with special focus on Shiga toxin-producing Escherichia coli (STEC), also called verotoxin-producing E. coli (VTEC) or enterohaemorrhagic E. coli (EHEC). Available from: http://www.efsa.europa.eu/en/press/news/110611.htm

2. Urgent advice on the public health risk of Shiga-toxin producing Escherichia coli in fresh vegetables. European Food Safety Authority, Available from: http://www.efsa.europa.eu/en/efsajournal/pub/2274.htm

IFH Guidelines and Training Resources on Home Hygiene 1. Recommendations for selection of suitable hygiene procedures for use in the domestic environment. International Scientific Forum on Home Hygiene. Available from: http://www.ifh- homehygiene.org/IntegratedCRD.nsf/70f1953cec47d5458025750700035d86/24 401f935e57e79e802574e200391c43?OpenDocument 2. Guidelines for prevention of infection and cross infection in the domestic environment: focus on issues in developing countries. International Scientific Forum on Home Hygiene. Available from : http://www.ifh- homehygiene.org/IntegratedCRD.nsf/70f1953cec47d5458025750700035d86/24 eb06345354d067802574e1005a075d?OpenDocument 3. Home Hygiene - prevention of infection at home: a training resource for carers and their trainers. International Scientific Forum on Home Hygiene. Available from: http://www.ifh- homehygiene.org/IntegratedCRD.nsf/571fd4bd2ff8f2118025750700031676/9aaa eb306bb3c50c80257522004b4fdc?OpenDocument 4. Home Hygiene in Developing Countries: Prevention of Infection in the Home and Peridomestic Setting. A training resource for teachers and community health professionals in developing countries. International Scientific Forum on Home Hygiene. Available from: http://www.ifh- homehygiene.org/IntegratedCRD.nsf/571fd4bd2ff8f2118025750700031676/1915 5ab46073e67f8025752200546d83?OpenDocument

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