Bench-to-bedside review: Clostridium difficile colitis.

In recent years, the incidence and severity of Clostridium difficile-associated disease (CDAD) have increased dramatically. Beginning in 2000, widespread regional outbreaks associated with a previously uncommon hypervirulent strain of C. difficile have occurred in North America and Europe. Most likely because of increased toxin production as well as other virulence factors, this epidemic strain has caused more severe and refractory disease leading to complications, including intensive care unit admission, colectomies, and death. Worldwide increasing use of fluoroquinolones and cephalosporins has likely contributed to the proliferation of this epidemic strain, which is highly resistant to both. The elderly have been disproportionately affected by CDAD, but C. difficile has also recently emerged in populations previously considered to be at low risk, including healthy outpatients and peripartum women, although it is unknown if these cases are related to the epidemic strain. Nevertheless, transmission within hospitals is the major source of C. difficile acquisition, and previous or concurrent antimicrobial use is almost universal among cases. Applying current evidence-based strategies for management and prevention is critically important, and clinicians should maintain an awareness of the changing epidemiology of CDAD and take measures to reduce the risk of disease in patients.