Clostridium difficile

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What is a clostridium difficile infection?

A clostridium difficile infection (CDI) is a type of bacterial infection that can affect the digestive system. It most commonly affects people who are staying in hospital.

The symptoms of CDI can range from mild to severe and include:

  • diarrhoea
  • a high temperature (fever) of or above 38C (100.4F)
  • painful abdominal cramps

CDI can also cause life threatening complications such as severe swelling of the bowel due to a build-up of gas (this type of swelling is known as toxic megacolon).

Read more about the

symptoms of clostridium difficile
and complications of a clostridium difficile infection.


Spores of the C. difficile bacteria can be passed out of the human body in faeces (stools) and can survive for many weeks, and sometimes months, on objects and surfaces.

If you touch a contaminated object or surface and then touch your nose or mouth you can ingest the bacteria

The C. difficile bacteria do not usually cause any problems in healthy people. However, some antibiotics can interfere with the balance of 'good' bacteria in the gut.

When this happens, C. difficile bacteria can multiply and produce toxins (poisons), which cause symptoms such as diarrhoea.

Read more about the

causes of a clostridium difficile infection


A mild CDI can usually be controlled by withdrawing treatment with the antibiotics causing the infection.

More severe cases can be treated using the following antibiotics:

  • vancomycin
  • metronidazole

The condition usually responds well to treatment, with symptoms improving in 2-3 days and clearing up completely within 7-10 days.

However a return of symptoms (relapse) is common occurring in around 1 in 4 cases. A relapse will require further treatment. Some people have two or more relapses.

Life threatening cases may need surgery to remove a damaged section of the bowel which is required in around 1 in a 100 cases.

Severe cases of CDI – especially when they occur in people who were already very ill – can be fatal.

Read more about

treating a clostridium difficile infection


C. difficile bacteria spread very easily. Despite this, CDIs can usually be prevented by practising good hygiene in healthcare environments, such as washing hands regularly and cleaning surfaces using products containing bleach.

If you are visiting someone in hospital you can reduce the risk of spreading infection by washing your hands before and after entering the ward. Alcohol hand gel is not effective against C. difficile spores, so the use of soap and water is essential.

Read more about

preventing a clostridium difficile infection.

Who is affected

As CDIs are usually caused by antibiotics, the majority of cases happen in a healthcare environment, such as a hospital or care home.

Older people are most at risk from infection. People aged over 65 account for three quarters of all cases.

In recent years, the number of CDIs has fallen rapidly.

Unfortunately a new strain of the C. difficile bacteria, called NAP1/027, has emerged in recent years. This new strain tends to cause more severe infection.

There has also been an increase of CDI cases occurring outside of a healthcare setting (known as community-acquired clostridium difficile infection).

Clostridium difficile infection symptoms

The symptoms of a clostridium difficile infection (CDI) usually develop when you are taking, or have just finished taking, an antibiotic.

Occasionally symptoms may appear up to 10 weeks after you finish taking antibiotics.

The most common symptoms of a mild to moderate CDI are:

  • regular bouts of usually foul-smelling, watery
    ; which can sometimes be blood stained; most people have around 3-5 bouts of diarrhoea a day
  • abdominal cramping and pain

In more severe cases of CDI your colon (large bowel) can become inflamed, which is known as colitis.

Symptoms of colitis include:

  • more frequent bouts of diarrhoea; between 10-15 a day
  • a high temperature (fever) of or above 38C (100.4F)
  • more severe abdominal cramping
  • dehydration
    (not having enough fluid in your body)
  • feeling sick
  • loss of appetite
  • weight loss

When to seek medical advice

Diarrhoea can be a common side effect of antibiotics so having diarrhoea while taking antibiotics does not necessarily mean you have a CDI.

If the diarrhoea persists after finishing your course of antibiotics you should contact your doctor for advice.

You should also contact your doctor if you experience additional symptoms such as a high temperature or abdominal cramps.

Causes of clostridium difficile infections

Clostridium difficile (C. difficile) are anaerobic bacteria. This means they do not need oxygen to survive and multiply. Therefore, they usually survives well in the colon (bowel), where there is very little oxygen.

C. difficile does not usually affect healthy children and adults. This is because the healthy 'good' bacteria in the intestine keep it under control. However, some antibiotics can interfere with the healthy balance of bacteria.

When this happens, C. difficile bacteria can multiply and produce toxins (poisons), which cause illness. At this point, a person is said to have a clostridium difficile infection (CDI).

Spread of infection

Once C. difficile bacteria start to produce toxins, the bacteria can spread easily. This is because the bacteria produce spores (a form of cell that is highly resistant to chemicals), which leave the body in an infected person's


The spores are resistant to conditions outside the body and can contaminate their surroundings, such as toilets, bedclothes, skin and clothing.

The spores or bacteria are spread by the hands of healthcare staff and other people who come into contact with infected patients or contaminated surfaces.

The spores can also be spread through the air (while making the bed, for example). They can survive for a long time outside the body unless they are destroyed through very thorough cleaning.

Most at risk

People most vulnerable to a C. difficile infection are those who:

  • have been treated with broad-spectrum antibiotics (antibiotics that can treat different types of bacteria), such as amoxicillin and cefalexin
  • have had to stay for a long time in a healthcare setting, such as a hospital
  • are over 65 years old
  • have a serious underlying illness or condition
  • have a weakened immune system, which can be due to a condition such as
    or a side effect of a treatment such as
  • have had many enemas (injections of liquid into the back passage) or digestive surgery

The majority of infections occur in places where many people take antibiotics and are in close contact with each other, such as hospitals and nursing homes. A number of precautions can be taken to help reduce the spread of infection. Read more about

preventing a clostridium difficile infection

Clostridium difficile infection diagnosis

Clostridium difficile infection (CDI) is diagnosed by carrying out laboratory tests on a sample of the infected person's faeces (stools or ‘poo’).

If a CDI is present, the test will show C. difficile toxins in the sample of faeces.

You may also be given a

blood test
to measure the amount of white blood cells in your blood.

A very high level of white blood cells would usually indicate a more severe form of CDI which could have implications for your treatment.

Blood tests can also detect mineral imbalances that can occur in the blood as a result of


If your symptoms suggest you may have complications affecting your colon (bowel) it may need to be examined. This can be done:

  • directly – by placing a flexible tube containing a camera and a light source up into your rectum (back passage) and then into your colon; this is known as a colonoscopy
  • indirectly – by using a
    computer tomography (CT) scan
    ; this takes a series of X-rays and uses a computer to assemble the scans into a more detailed image of your colon

Faeces Stool (also known as faeces) is the solid waste matter that is passed from the body as a bowel movement.

Clostridium difficile infection treatment

You will only need treatment for a clostridium difficile infection (CDI) if you have symptoms.

No treatment is needed if the bacteria are living harmlessly in your digestive system.

Mild CDI

If you have mild symptoms of a CDI, it is best to stop taking the antibiotics that may have caused the infection, if possible. This will allow the natural 'good' bacteria to regrow in your gut. In many cases where the symptoms are mild, stopping the antibiotics is often enough to ease the symptoms and clear the infection.

Moderate to severe CDI

If you have symptoms that are more troublesome, such as severe diarrhoea or colitis (swelling and irritation of the bowel) you may need to take an antibiotic that can kill C. difficile bacteria.

This will usually be either metronidazole or vancomycin, which should ease the symptoms within two to three days, though it can take around 7-10 days to make a complete recovery

Possible side effects of these antibiotics are stomach ache, feeling sick and being sick.

Treating relapses

In around 1 in 4 cases the symptoms of CDI return; usually within a week of completing treatment. This is known as a relapse.

The recommended treatment option for a first relapse is usually to repeat the original course of treatment.

If you experience a second relapse, then a 14 day course of vancomycin may be recommended followed by further 10-14 day course of an additional antibiotic such as fidaxomicin (a new antibiotic introduced in 2011) or rifaximin.

If you then go on to experience further relapses you may be referred to a specialist in the treatment of persistent CDIs.

There are a number of treatment options available to you:

  • probiotics can be given in combination with antibiotics – probiotic supplements are designed to stimulate the growth of ‘good’ bacteria (although the evidence of their effectiveness in treating CDIs is inconclusive)
  • immunoglobulins – you are injected with a medication designed to stimulate the production of antibodies to fight off the infection

Faecal transplantation

Another new treatment option for recurring CDIs is called faecal transplantation. This is when a sample of liquid faecal matter (stools or ‘poo’) is taken from a healthy donor and then placed inside your colon, by way of a catheter (a tube) that is stuck down your nose and into your colon.

The donated sample can then help stimulate the production of ‘good’ bacteria and restore the normal balance of bacteria inside your digestive system.

While this may sound unpleasant, the treatment does have good results. Initial studies have found the treatment effective in around four out of five cases. However, access to this type of treatment is currently limited.

Preventing a clostridium difficile infection

Clostridium difficile bacteria can spread easily, particularly in healthcare environments, such as a hospital or care home. It may not be possible to prevent the bacteria from spreading altogether, but a number of precautions can be taken to reduce the risk of infection.

Advice for visitors

If you are visiting a person in a healthcare environment who has diarrhoea or a stomach upset, try to avoid taking any children under the age of 12 with you. You should also:

  • wash your hands with soap and water when entering and leaving ward areas
  • avoid healthcare environments if you are feeling unwell or have recently had diarrhoea
  • observe visiting hours and all visiting guidelines

Healthcare environment

Healthcare workers should wear disposable gloves and aprons when caring for anyone who has a C. difficile infection. Whenever possible, people who are infected with C. difficile should have their own room and toilet facilities to avoid passing the infection onto others.

Staff, patients and visitors should be encouraged to wash their hands regularly and thoroughly. Alcohol hand gel is not effective against C. difficile spores, so the use of soap and water is essential.

Surfaces that may have come into contact with the bacteria or spores, such as toilets, the floor around toilets, bedpans and beds, should also be cleaned thoroughly with water and a cleaning product containing bleach.

Complications of a clostridium difficile infection

Complications of a Clostridium difficile infection (CDI) are uncommon, occurring in around 1 in 35 cases. When they do occur, they can be very serious.

Risk factors that increase the chance of a person developing complications include:

Some of the most serious complications of a CDI are discussed below.

Dehydration and acute kidney failure

Frequent bouts of

can quickly lead to

Being severely dehydrated reduces the supply of blood to your kidneys, so they stop working properly (one of the main functions of the kidneys is to filter waste products out of your blood). This is known as acute kidney failure.

Symptoms of acute kidney failure include:

  • passing much less urine than you used to
  • swelling of the feet, ankles and/or legs due to a build-up of fluid
  • drowsiness
  • mental confusion

Acute kidney failure can be treated by tackling the underlying infection while also restoring fluids to your body, usually by way of a drip.

Usually the kidneys will begin working again after treatment.

Perforated colon and peritonitis

If your colon becomes severely inflamed due to infection there is a risk it could split open (perforate) and allow bacteria to move out of the colon and infect the thin layer of tissue that lines the inside of the abdomen (peritoneum). This type of infection is known as


Symptoms of peritonitis
often come on quickly and include:

  • severe abdominal pain
  • a high temperature (fever) of 38C (100.4F) or above
  • chills

Peritonitis is a medical emergency - if left untreated, the infection can quickly spread to other parts of the body, causing multiple organ failure and eventually death.

In many cases of peritonitis it will be necessary to remove your colon during surgery (colectomy). Without a colon, you will be unable to pass stools out of your body in the usual way. You’ll need a further operation, where the end of your small intestine is re-routed to an opening in your abdomen known as a stoma. An external bag is attached to the opening to collect waste products. This procedure is known as an


Toxic megacolon

Toxic megacolon is when gases can get trapped in the colon, causing it to swell.

This is dangerous as it can send the body into shock (a sudden drop in blood pressure), split the colon and lead to peritonitis.

The symptoms of a toxic megacolon include:

  • abdominal pain
  • dehydration
  • high body temperature (40C or 104F)
  • a rapid heart rate

Toxic megacolon can be treated with intravenous fluids, antibiotics and

. At the same time, a tube will need to be inserted into your rectum and colon so the gas can be withdrawn and your colon decompressed.

In more severe cases, a colectomy will need to be performed.

Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.