Clostridium difficile infection  (CDI) is the most important cause of hospital-acquired diarrhoea. CDI ranges from mild to severe diarrhoea to, more unusually, severe inflammation of the bowel (known as pseudomembranous colitis). People who have been treated with broad spectrum antibiotics, people with serious underlying illnesses, and older people are at greatest risk – more than 80% of CDIs reported are in people aged over 65 years.
In the quarter up to December 2011 there were 4345 reports of CDI, equivalent to 34 per 100,000 population in England. A recent systematic review found that in Europe the incremental cost of CDI ranged from £4577 to £8843 driven primarily by increased length of hospital stay. According to a Department of Health impact assessment report in 2010, the best estimate of costs to the NHS associated with a CDI is around £10,000.
Mild cases of CDI associated with treatment with broad spectrum antibiotics may recover after stopping the causative antibiotic therapy, although this approach is not straightforward in clinical practice given the concern that symptoms may worsen. Conservative treatment often is not sufficient for moderate to more severe cases and targeted antibiotic therapy is required, most commonly with oral metronidazole or vancomycin. Both drugs are, in most cases, effective in treating CDI, but about a quarter of patients who initially respond to these agents have a clinical recurrence.
 Wiegand PN, Nathwani D, Wilcox MH et al. (2012) Clinical and economic burden of Clostridium difficile infection in Europe: a systematic review of healthcare-facility-acquired infection. Journal of Hospital Infections. April 2012 [published online ahead of print]
 Department of Health (2012) Quality and Outcomes Framework 2011/2012. Impact assessment No. 5014, [accessed 25 April 2012]