E. coli - should you be worried?

Escherichia Coli (E. coli) is a common bacterium which can have nasty effects. Although mostly harmless, rare strains can cause complications. Recent outbreaks in the UK of a rare strain known as E. coli 0157 has sparked public concern. With over 150 cases and two deaths, you can be forgiven for having some worry. Current reports suggest the outbreak is clustered in the South West, with a possible source originating from the Mediterranean in the form of salad. As horrible as things sound, remember that newspapers love drama. Sorry to dial things down.

E. coli is a common bug found in our digestive systems. It may be caught by eating contaminated food, swimming in dirty water, or contact with animal or human faecal matter. In rare cases it may cause gastroenteritis, which is infection within the tummy. Symptoms are usually temporary and include nausea, diarrhoea (which may be bloody), tiredness, fever and headache.

In most cases antibiotics may not be used and all that is needed is fluids. In rare cases the deadlier strains, such as E. coli 0157, can have more severe effects. The presence of certain toxins in the bug cause reactions in the body which can lead to bleeding, anaemia and kidney failure. This is called Haemolytic Uraemic Syndrome (HUS) and is very rare.

In HUS, we see tiny clots and red blood cell break down in the tiny vessels of the body. This causes anaemia, which is a scarcity of red cells. If this becomes severe enough, you can feel tired and sick. HUS also causes thromocytopaenia, which is a low platelet count. Platelets are part of your natural clotting mechanisms, so less platelets leads to more bleeding.

In the worst case scenario, we can see kidney failure, which leads to the accumulation of toxins in the body which can be fatal. Uraemia is the presence of toxic metabolites in the body, which can cause confusion and organ problems.

Symptoms of HUS will include nausea, diarrhoea and cramps, but may also include symptoms of anaemia, bleeding and kidney problems. Pale skin, shortness of breath, blood in the urine and a fast heartbeat may indicate bleeding, whereas a reduced need to pass water and lower back pain may suggest kidney injury. Confusion may indicate brain involvement.

In these cases, hospital admission with intravenous fluids is necessary. The use of antibiotics is controversial and supportive management is preferred. Rarely the toxic effects are so severe that intensive care is needed.

As bleak as it all sounds, most people recover. Up to 85% of those with E. coli 0157 will have kidney involvement, but over half will have no lasting problem. Around 20% of those experiencing kidney damage may go on to develop high blood pressure, which is managed with medication but increases the risk of heart disease and stroke. Kidney failure is rare, and the earlier E. coli 0157 is suspected the better the treatment outcome.

'Outbreaks' of E. coli usually refer to the 0157 variety. This is due to the more severe symptoms and need for hospital admission bringing it to public attention. Simple gastroenteritis is usually not investigated so it rarely becomes public knowledge. We love a good plague.

So although E. coli 0157 may seem dramatic, its overall mortality is very low. Most patients will get better, and if you look at the most recent outbreak, just over 1% of cases were fatal. It is likely that these cases were in those who were especially susceptible. This is the case for most infective diseases.

How can I prevent becoming ill due to E. coli?

Simple hygiene measures will help to reduce the risk of contracting the disease. Avoiding contaminated areas, washing hands and cleaning kitchen areas is important. Washing raw food, removing any soil and cooking meats thoroughly will reduce the risk further. Avoid contact with those who you suspect have an infection, and if you have an infection do not prepare food until 48 hours after your last symptom. Avoid swimming in water near infected areas, and listen to public health (including common sense) advice.

So there you have it. E. coli is common, and usually harmless, and dangerous strains like E.coli 0157 are rare and avoidable with simple measures. If you suspect infection, contact your local doctor. And don't panic.
 
Any opinions above are the author's alone. Guidance is based the best available evidence at the time of writing. Online recommendation is no substitute for seeing your own doctor and should not be taken as medical advice. There are no conflicts of interest

Ben is a young NHS doctor in the Southwest. His interests include neurology, health communication, and medical ethics. He is also an avid advocate of compassionate care and quality improvement, running a project in the Southwest around medical humanities. Please follow and support: Dr Janaway on Facebook Dr Janaway on Twitter

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