Clostridium difficile – A Pathogen on the Move

Clostridium difficile has emerged as the scourge of modern hospitals and is the leading cause of nosocomial infection worldwide. Recent years have seen the increase in virulent and highly transmissible clonal lineages that has brought the pathogen into the public and political eye. The transcontinental spread of these strains coupled with the ferocity of the disease, means a better understanding of the basic pathogenesis and epidemiology of C. difficile is a current imperative. There is no doubting the seriousness of C. difficile in terms of affecting human health and its economic impact, yet remarkably little is understood about the pathogen and how it persists and causes disease. Concomitant with the emergence of highly virulent strains has been a deeper understanding of the pathogen and disease, fuelled by the application of genomics-based methodology. This chapter updates our understanding of the epidemiology, pathogenesis and evolution of this obdurate pathogen based on recent genomic advances.