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Escherichia coli O157: infection and infection
prevention through hygiene in the home
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 O157 in the home (household) setting.
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 O157 and/or those who are
responsible for providing guidance to the public on coping with hygiene issues
associated with E. coli O157.
What is E. coli O157?
E. coli O157 is one of hundreds of strains of the bacterium Escherichia coli. Although
most strains of E. coli are harmless and live in the intestines of healthy humans and
animals, this particular strain produces a powerful verocytotoxin, a poison that plays
a part in making the bacteria so harmful, causing severe illness. It is sometimes
referred to as verocytotoxin producing E. coli (VTEC) or enterohaemorrhagic E.coli
(EHEC).
E. coli O157 was first recognised as a cause of illness in 1982 during an outbreak of
severe bloody diarrhoea; the outbreak was traced to contaminated hamburgers. E.
coli O157 can cause a range of symptoms from mild diarrhoea to bloody diarrhoea
(haemorrhagic colitis). Haemorrhagic colitis is often accompanied by severe
abdominal cramps but usually without fever. The incubation period for infection
before the onset of diarrhoea can range from 1 to 14 days. Symptoms usually resolve
within two weeks.
Where is E. coli O157 found?
Over 15% of healthy cattle may carry E. coli O157 in their gut. Animals are usually
unaffected, although a few may become ill. Meat can become contaminated during
slaughter, and organisms can be thoroughly mixed into beef when it is ground.
Bacteria present on the cow's udders or on equipment may get into unpasteurised
milk. The organism has also been isolated from 7% of sheep, and there are reports
of it being isolated from other animals.
E. coli O157 is also found in the gut and faeces of people who have become infected.
In some cases people can act as symptomless carriers
Most data on GI disease comes from outbreaks reported to national surveillance. The
annual Community Summary Report by the European Food Safety Authority (EFSA)
and European Centre for Disease Prevention and Control (ECDC), gives an overview
of the latest trends and figures on the occurrence of zoonoses and zoonotic agents in
humans, animals and foodstuffs in the 27 European Union (EU) Member States and
the European Free Trade Association (EFTA) countries.1 Further information on the
incidence and prevalence of E. coli O157 infection can be found European Centre for
Disease Prevention and Control Annual Epidemiological Report.2 These publications
are updated annually. Data for the US is generated through the National Outbreak
Reporting System.3
How does E. coli O157 get into the home?
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Through contaminated raw meat and unpasteurised milk
The 2012 European Community Summary Report on foodborne infections
reported that Bovine meat is believed to be a major source of food-borne
VTEC infections for humans. In 2010, 12 member states reported testing of
8,566 bovine meat units of which 0.5 % were found to be VTEC-positive and
0.1 % VTEC O157-positive.
 Through cooked meat products such as sausages and pies which have
become cross-contaminated from raw contaminated foods on the premises
due to poor hygiene practices.
Through fresh vegetables which have become contaminated from raw
contaminated sewage or contaminated water.
Farm animal faeces are a high risk source of E. coli O157: Family members can
“pick up” the organism during visits to “animal exhibits” e.g. farms and ‘petting
zoos’.
An infected family member may act as the primary source of infection in the
home.
How do people become infected?
E. coli spreads via the common routes for stomach bugs. It 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)
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Food can be contaminated with E.coli O157 because it has not been properly
cooked or properly stored, or because, after cooking, it has been contaminated
from “dirty hands” or contact with contaminated raw food.
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. The hands can also become
contaminated by direct contact with animals or their faeces during farm visits
This means that:
1. Foodborne (or waterborne) infection can occur by:
 Eating undercooked meat especially minced beef produced as burgers.
 Drinking unpasteurised milk, or milk that has been contaminated after
pasteurisation.
 Drinking water supplies contaminated with faeces; this is more likely to occur with
private supplies.
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Eating unwashed, unpeeled vegetables or fruit fertilised with infected manure.
Direct or indirect cross-contamination from contaminated raw food (e.g. poultry)
to other food which may be eaten without further cooking, e.g. salads.
Infected food handlers (who may have no symptoms of illness) can contaminate
food during preparation and handling.
Outbreaks have been associated also with other foods: yoghurt, cooked meats,
meat pies, cheese, dry cured salami, raw vegetables, unpasteurised apple juice
and water.
Current data indicates that eating contaminated (usually undercooked) ground beef is
still the single most important cause of foodborne E. coli O157 illness. However, leafy
green vegetables are the second most significant cause as they are subject to
contamination and they are eaten raw.
In a US study, of 23 patients infected with E. coli 0157, 80% of the cases were
thought to have originated from consumption of hamburgers in the home and food
preparers in those homes were significantly less likely to report washing their hands
or work surfaces. The transmission was believed to have occurred more often when
the hands of food preparers were allowed to cross-contaminate other food and
utensils
During the investigation of a 2009 outbreak of E. coli O157:H7 in a US child-care
centre, illness the overall attack rate was 15%. Three children were hospitalised, one
received a diagnosis of haemolytic uremic syndrome, but no deaths were reported.
The median duration of shedding of E. coli was 22 days (range, 2−48 days). The
authors concluded that their findings suggest that household transmission
contributed to the spread of the infection.4
2. Person-to-person spread of infection:
Person-to-person contact in families, nurseries, and infant schools is an important
mode of transmission. Bacteria in diarrhoeal stools of infected persons can be
passed from one person to another if hygiene or handwashing 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.
EHEC/VTEC strains, including O157, readily transmit in the home to cause
secondary 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%
Further information on the occurrence, survival and transmission of Salmonella in the
home can be found in a 2013 IFH report5
3. Infection associated with visits to farms and other animal exhibits
Family members can “pick up” the organism on their hands and then transfer the
organisms directly from hand to mouth during visits to “animal exhibits” e.g. farms.
Indirect contact with infected animals, e.g. via domestic animals such as dogs or
cats, and via items of clothing contaminated with cattle faeces can also lead to
infection.
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Incidence of E. coli O157 infections
The highest incidence of reported cases occurs in children. In addition to children,
the elderly are known to be susceptible to E. coli O157 infection. While these
populations are more susceptible to illness, people of all ages can suffer infection
from E. coli O157.
Reports of haemorrhagic colitis infections are uncommon, but this is probably not
reflective of their true frequency. Due to unmistakable symptoms of visible blood in
severe cases, these victims usually seek medical attention, but less severe cases are
probably more numerous. Hospitalisation is a common occurrence with E. coli O157
infection. It is estimated there are 2,100 hospitalisations annually in the United
States.
The 2012 European Community Summary Report on foodborne infections reported
a total of 4,000 confirmed verotoxigenic Escherichia coli infections in 2010, and most
of these cases were caused by the serogroup O157. The numbers of the reported
verotoxigenic Escherichia coli human cases have been increasing in the European
Union since 2008. In animals and food most verotoxigenic Escherichia coli-positive
findings were made from cattle and bovine meat, but the bacteria were also detected
in other animal species and foodstuffs. The majority of reported human VTEC
infections are sporadic cases.
A 2000 study of UK outbreaks suggested that more than half of E. coli O157
outbreaks are transmitted by non-foodborne routes. The 2013 summary of acute
gastroenteritis using data reported the US national Reporting system for 2009-2011
reported 69 confirmed or suspected outbreaks of Campylobacter infection and 1550
illnesses (1.7 of total illnesses) 52 hospitalisations and zero deaths.3
In 1999, Mead et al reporting on gastrointestinal illness in the US estimated that the
annual incidence of E. coli O157 infections was 73,480, 15% of which were nonfoodborne. The 2013 summary of acute gastroenteritis using data reported the US
national Reporting system for 2009-2011 reported 101 confirmed or suspected
outbreaks of infection involving Shiga toxin-producing E. coli and 1091 illnesses (1.2
of total illnesses) 250 hospitalisations and 9 deaths.3
Further information on the incidence and prevalence of E. coli O157 infections can be
found in a 2009 IFH report6
Who is at risk?
Anyone can be infected by E.coli O157. Those most at risk to E.coli O157 are
children and the elderly.
Symptoms and complications of disease
Patients infected with E. coli O157 typically develop acute stomach pain and severe
diarrhoea which is watery at first but then becomes bloody. Mild fever and maybe
vomiting may also result
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In some persons, particularly children under 5 years of age and the elderly, the
infection can also cause a complication called haemolytic uraemic syndrome (HUS),
characterised by renal failure and haemolytic anaemia. HUS is the major cause of
acute renal failure in children in Western Europe and North America. HUS develops
in up to 10% of patients infected with E. coli O157. The fatality rate of E. coli O157
infection is very variable and depends on the ages of the groups affected. Fatality
rates ranging from 1 to 5% have been reported but may be much higher in some
institutional outbreaks. In the US it is estimated that 61 people with E. coli O157
infection die each year.
Preventing the spread of E. coli O157 infection in the home
In situations where there is risk of spread of E. coli O157 infection in the home the
following hygiene measures should be rigorously implemented. It must be
remembered that E. coli O157 can also be shed by people who have no symptoms –
both those who have apparently recovered and those who have not developed
symptoms.
Since the risk of introducing E. coli O157 into the home, either via people, foods or
domestic pets is constant and may not be recognised until an outbreak of infection
occurs within the family, this means that good day-to-day hygiene including good
food hygiene makes sense
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:
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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 O157 in the
home, it is suggested that handwashing followed by use of an alcohol
rub/sanitiser should be encouraged.
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
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:
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wash in a washing machine at 60°C using a powder or tablet detergent
containing active oxygen bleach (see ingredients on back of pack)
- clean with detergent and warm water, rinse and then immerse in disinfectant
solution which is effective against E.coli O157 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 O157 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 and 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 O157. Either:
- for preference, wash at 60C or above, using a powder or tablet detergent
containing active oxygen bleach (see ingredients on back of pack).
- alternatively wash at 40C with a powder or tablet detergent containing active
oxygen bleach (see ingredients on back of pack)
Note: washing at 40°C without the addition of bleach will not destroy E coli O157
 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 handwashing, 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
Rigorous food hygiene is important in preventing the spread of E. coli O157 in the
home. 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 food source of E. coli O157 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.
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coli O157**. 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 cooked food are kept
separate from cooked foods.
In an outbreak situation where the primary source has not been identified and
removed from circulation, avoid or take particular care with known sources such as
beef, hamburgers, cooked meat products, unpasteurised milk and unwashed
vegetables.
Avoiding infection from visits to farms or other animal exhibits
Pay particular attention to hygiene after visiting farms, land occupied by farm animals
and avoid contact with animal faeces and places likely to be contaminated with it.
Wash hands thoroughly with soap and water immediately after the visit.
*How to wash hands:
Handwashing “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 handwashing is:
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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:
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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, handwashing followed
use of an alcohol rub/sanitiser should be encouraged
One very simple thing which people can do which can significantly reduce the risk of
disease is to avoid putting their fingers to their mouth.
**Disinfectants and disinfectant cleaners
Make sure you use a disinfectant or disinfectant/cleaner such as a bleach-based
product, which is active against E. coli O157. For more details on choosing the
appropriate disinfectant, see the IFH information sheet “Cleaning and disinfection:
Chemical Disinfectants Explained”. Consult the manufacturers’ instructions for
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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 5000ppm 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 O157
 UK
National
Electronic
Library
on
Infections
(NELI)
.
http://www.neli.org.uk/IntegratedCRD.nsf/NeLI_Organisms1?OpenForm&Seq=1#_
RefreshKW_Bacteria
 Public
Health
England:
.
http://www.hpa.org.uk/Topics/InfectiousDiseases/InfectionsAZ/EscherichiaColiO15
7/
 US Centre for Disease Control and Prevention. http://www.cdc.gov/ecoli/
 European
Centre
for
Disease
Control
and
Prevention:
http://www.ecdc.europa.eu/en/healthtopics/salmonellosis/Pages/index.aspx
IFH Guidelines and Training Resources on Home Hygiene
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Guidelines for prevention of infection and cross infection the domestic
environment. International Scientific Forum on Home Hygiene. Available from:
http://www.ifh-homehygiene.com/best-practice-care-guideline/guidelinesprevention-infection-and-cross-infection-domestic
Guidelines for prevention of infection and cross infection the domestic
environment: focus on issues in developing countries. International Scientific
Forum
on
Home
Hygiene.
Available
from:
http://www.ifhhomehygiene.org/best-practice-care-guideline/guidelines-preventioninfection-and-cross-infection-domestic-0
Recommendations for suitable procedure for use in the domestic environment
(2001). International Scientific Forum on Home Hygiene. http://www.ifhhomehygiene.org/best-practice-care-guideline/recommendations-suitableprocedure-use-domestic-environment-2001
Home hygiene - prevention of infection at home: a training resource for carers
and their trainers. (2003) International Scientific Forum on Home Hygiene.
Available from: http://www.ifh-homehygiene.com/best-practice-training/homehygiene-%E2%80%93-prevention-infection-home-training-resource-carersand-their
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: www.ifh-homehygiene.org/best-practicetraining/home-hygiene-developing-countries-prevention-infection-home-andperi-domestic. (Also available in Russian, Urdu and Bengali)
This fact sheet was last updated in 2014
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Further Information
1
2
3
4
5
6
The European Union Summary Report on Trends and Sources of Zoonoses,
Zoonotic Agents and Food-borne Outbreaks in 2010. Scientific report of EFSA and
ECDC Downloadable from http://www.efsa.europa.eu/en/efsajournal/doc/2597.pdf
European Centre for Disease Prevention and Control. Annual Epidemiological
Report 2013.
http://www.ecdc.europa.eu/en/publications/Publications/annual-epidemiologicalreport-2013.pdf
Hall AJ, Wikswo ME, Manikonda K, Roberts VA, Yoder JS, Gould LH. Acute
gastroenteritis surveillance through the National Outbreak Reporting System,
United States. Emerg Infect Dis. 2013. http://dx.doi.org/10.3201/eid1908.130482.
Gallagher L, Soyemi K et al Outbreak of Escherichia coli O157:H7 in a child care
center in Cook County, Illinois, with prolonged shedding and household
transmission. American Journal of Infection Control; 2013;41:936-8.
Bloomfield SF. Exner M, Signorelli C, Nath KJ, Scott EA. 2012. The chain of
infection transmission in the home and everyday life settings, and the role of
hygiene in reducing the risk of infection.
http://www.ifh-homehygiene.com/best-practice-review/chain-infectiontransmission-home-and-everyday-life-settings-and-role-hygiene
Bloomfield SF, Exner M, Fara GM, Nath KJ, Scott, EA; Van der Voorden C. The
global burden of hygiene-related diseases in relation to the home and community.
(2009) International Scientific Forum on Home Hygiene.
http://www.ifh-homehygiene.org/review/global-burden-hygiene-related-diseasesrelation-home-and-community.
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