Clostridium difficile are anaerobic bacteria. This means they do not need oxygen to survive and multiply. They therefore survive 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 bacteria normally present in the healthy bowel 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) that cause illness. At this point, a person is said to have a Clostridium difficile infection.

Spread of infection

Once C. difficile bacteria start to produce toxins, the bacteria can spread easily. This is because the bacteria are now producing spores (a much more resistant form of the cell) that leave the body in an infected person’s diarrhoea.

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

The spores of 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, for example while making the bed. They can survive for a long time outside the body unless they are removed by 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 in a healthcare setting for a long time
• are over 65 years old
• have a serious underlying illness or condition
• have a weakened immune system, which can be because of a condition such as diabetes or a side effect of a treatment such as chemotherapy
• have had surgery on the digestive system

Previously, the majority of infections occurred in places where many people take antibiotics and are in close contact with each other, such as hospitals and care homes.

Control measures have been effectively implemented to dramatically reduce the number of infections in healthcare settings. A number of precautions can be taken to help reduce the spread of infection.

Read more about preventing a Clostridium difficile infection. 

Complications of a Clostridium difficile infection are uncommon, occurring in around 1 in 35 cases. But when they do occur, they can be very serious.

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

• having a pre-existing condition that affects the colon, such as ulcerative colitis (a condition that causes persistent inflammation of the colon)
• being elderly – the older you are, the higher your risk of complications
• having another serious health condition, such as heart disease or chronic obstructive pulmonary disease (COPD)
• receiving treatments that are known to weaken the immune system, such as chemotherapy or a bone marrow transplant (also known as a stem cell transplant)

Some of the most serious complications of a C. difficile infection are discussed below.

Dehydration and acute kidney failure

Frequent bouts of diarrhoea can quickly lead to dehydration.

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 or legs because of 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 via a drip.

Usually the kidneys will begin working again after treatment.

Perforated colon and peritonitis

If your colon becomes severely inflamed after 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 peritonitis.

Symptoms of peritonitis often come on quickly and include:

• severe abdominal pain
• a high temperature (fever) of 38ºC (100.4ºF) 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 ileostomy.

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 (40ºC or 104ºF)
• a rapid heart rate

Toxic megacolon can be treated with intravenous fluids, antibiotics and steroids. 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 (the removal of a large part of the colon) will need to be performed.

Clostridium difficile infection is usually first diagnosed based on your symptoms and whether or not you have been taking antibiotics.

If necessary, diagnosis can be confirmed by carrying out laboratory tests on a sample of the infected person’s faeces.

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

Blood test

The number of white blood cells in your blood may also be measured in a blood test.

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

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

Colon (bowel) examination

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

• directly – by placing a flexible tube containing a camera and a light source up into your rectum (bottom) and then into your colon; this is known as a colonoscopy
• indirectly – by using a computer tomography (CT) scan, which 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.

A Clostridium difficile infection is a type of bacterial infection that can affect the digestive system. It most commonly affects people who have been treated with antibiotics.

The symptoms of a C. difficile infection can range from mild to severe and include:

• diarrhoea  
• a high temperature (fever) of above 38ºC (100.4ºF)
• painful abdominal cramps

A C. difficile infection can also lead to life-threatening complications such as severe swelling of the bowel from a build-up of gas (toxic megacolon).

Read more about the symptoms of Clostridium difficile and complications of a Clostridium difficile infection.

Causes

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 natural balance of normal bacteria in the gut that protects against C. difficile infection.

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

Read more about the causes of a Clostridium difficile infection.

Treatment

A mild C. difficile infection 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 two to three days and clearing up completely within 7 to 10 days.

However, relapse is common, occurring in around one in four cases, and requires further treatment. Some people have two or more relapses.

Life-threatening cases may need surgery to remove a damaged section of the bowel. This is needed in less than 1% of cases.

Severe cases of C. difficile infection can be fatal, especially when they occur in people who are already very ill.

Read more about treating a Clostridium difficile infection.

Prevention

C. difficile bacteria spread very easily. Despite this, C. difficile infections 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 with C. difficile, you can reduce the risk of spreading infection by washing your hands before and after entering the bed space. 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?

The majority of C. difficile cases occur in people who have had antibiotics. This may be in a healthcare setting, such as a hospital or care home, but can also occur at home without ever going to hospital.

Older people are most at risk from infection, especially those who are frail or with medical conditions. People over the age of 65 account for three-quarters of all cases.

In recent years, the number of C. difficile infections has fallen rapidly. There were 14,687 reported cases in England from April 2012 to March 2013, compared with 52,988 in 2007.

However, 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 in the number of C. difficile infections occurring outside a healthcare setting (known as community-acquired 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 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, especially after using the toilet or before eating
• 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 on to 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 that contains bleach.

The Map of Medicine is used by doctors throughout the NHS to determine the best treatment options for their patients. NHS Choices offers everyone in England exclusive and free access to this cutting-edge internet resource, which lets you see exactly what your doctor sees.

The information in the Map has been approved by the UK’s leading clinical experts, is based on the best available clinical evidence, and is continually updated. To take advantage of this unique resource go to:

Map of Medicine: Clostridium difficile

The symptoms of a Clostridium difficile infection 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 C. difficile infection are:

• regular bouts of usually foul-smelling, watery diarrhoea, which can sometimes be blood-stained (most people have around three to five bouts of diarrhoea a day)
• abdominal cramping and pain

In more severe cases, your colon (large bowel) can become inflamed – this is known as colitis.

Symptoms of colitis include:

• more frequent bouts of diarrhoea (between 10 and 15 a day)
• a high temperature (fever) of above 38ºC (100.4ºF)
• more severe abdominal cramping
• dehydration
• 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 C. difficile infection.

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

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

You will only need treatment for a Clostridium difficile infection if you have symptoms.

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

Mild infection

If you have mild symptoms of a C. difficile infection, it is best to stop taking the antibiotics that may have caused the infection, if possible. This will allow the natural mixture of 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 infection

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.

The first treatment will usually be metronidazole, but vancomycin or fidaxomicin may be used as an alternative in severe cases. This should ease the symptoms within two to three days, though it can take around 7 to 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 one in four cases, the symptoms of C. difficile infection 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, a 14-day course of vancomycin may be recommended, or an additional antibiotic such as fidaxomicin or rifaximin.

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

There are a number of treatment options available:

• a longer course of vancomycin – the dose is gradually reduced over several weeks
• repeat courses of antibiotics such as fidaxomicin  
• faecal transplantation
• immunoglobulins – these contain concentrated antibodies that are prepared from blood donations

Faecal transplantation

Another newer treatment option for recurring C. difficile infections is faecal transplantation. This involves a sample of faeces being taken from a healthy donor and placed into the colon of someone with a C. difficile infection using a catheter. Alternatively, it may be placed using a thin tube through the nose into the small bowel below the stomach.

The donated sample restores the normal balance of bacteria inside your digestive system with that from the healthy donor.

While this may sound unpleasant, the treatment does have very good results, with a success rate of more than 90%, and is probably the best treatment currently available. However, access to this type of treatment may be limited.