Prognosis in Clostridium difficile infection complicating inflammatory bowel disease

Since the earliest descriptions of Clostridium difficile as a cause of pseudomembranous colitis,1 clinicians have been familiar with the typical clinical setting in which infection can arise. It is well recognised that, classically, infection follows exposure to antibiotics targeting gut anaerobes and that transmission occurs nosocomially from one host to another.2 Yet, it has also been appreciated that the role that this Gram-positive bacillus plays in the colonic flora is complex and the circumstances that promote infection are variable. Early on, for instance, the term C difficile-associated disease (CDAD) came into use as it became apparent that positive stool testing failed to distinguish between an asymptomatic carrier state and true infection. Adoption of this term is an example of how physicians have had to adjust to the knowledge that has accumulated about this opportunistic organism. Over time, our understanding of C difficile has continued to expand and it is now known that infection can occur under a variety of conditions, in disparate settings, with a wide spectrum of severity and can recur despite treatment.3

In the past several years, some disturbing reports about C difficile have compelled the health care community to revisit its epidemiological and clinical importance. For one, several studies indicate a dramatic increase in the incidence of CDAD. Incidence has doubled in 10 years or less, and this has been demonstrated within various different patient populations and health care settings.4 5 Emergence of an epidemic strain of C difficile, characterised by greater virulence and conferring higher morbidity, explains part of this trend.6 7 Furthermore, clinicians increasingly recognise that CDAD may occur without prior antibiotic exposure. Controversy persists as to whom to treat and how best to treat, particularly given the development of increasing resistance to metronidazole.8^–10 Even …