Clostridium difficile (C. diff) is a bacterium that is present naturally in the gut of around 3% of adults and 66% of children.

C. diff does not cause any problems in healthy people. However, some antibiotics that are used to treat other health conditions can interfere with the balance of 'good' bacteria in the gut. When this happens, C. diff bacteria can multiply and cause symptoms such as diarrhea and fever.

As C. diff infections are usually caused by antibiotics, most cases usually happen in a healthcare environment, such as a hospital, or care home. Older people are most at risk from infection, with the majority of cases (80%) occurring in people over the age of 65.

Most people with a C. diff infection make a full recovery. However, in very rare cases the infection can be fatal.

In most cases, C. diff infections can be prevented by ensuring good hygiene practices in healthcare environments. However, it is extremely contagious and is spread very easily.