The mechanisms and efficacy of probiotics in the prevention of Clostridium difficile-associated diarrhoea.

The proportion and severity of Clostridium difficile-associated diarrhoea (CDAD) is increasing in health-care settings. Antibiotics remain the most important risk factor for CDAD, due to their limiting the ability of the gastrointestinal flora to inhibit C difficile colonisation. Probiotics have therefore been investigated for primary and secondary prophylaxis against CDAD, with varying success. This Review looks at the current literature for in-vitro and clinical evidence for probiotic use in the prevention of CDAD. Its aim is to examine the mechanisms through which probiotics interact with C difficile and its toxin, and the association of these mechanisms with the clinical evidence for probiotics in the prevention of this disease. The Review briefly describes the recent epidemiological changes in C difficile disease, and our current understanding of its pathophysiology. It looks at the safety profile of probiotics, highlighting patients groups in which their use is inappropriate, and attempts to synthesise guidance for clinicians interested in using probiotics to prevent CDAD within health-care institutions.