Nature Genetics pp 779 - 786

The genome sequence of Clostridium difficile, a major hospital acquired human pathogen, is published in the July issue of Nature Genetics. The spore-forming anaerobic bacterium is a leading cause of infectious diarrhea amongst hospital patients worldwide. The disease associated with C. difficile infection ranges from antibiotic-associated diarrhea to the more severe forms including life threatening pseudomembranous colitis – also referred to as antibiotic-associated colitis.

Julian Parkhill and colleagues sequenced C. difficile strain 630, a virulent and multidrug resistant strain, isolated from a hospital patient with severe pseudomembraneous colitis in Zurich, Switzerland. This strain had spread to several other patients in the same ward of the hospital, suggesting its transmissibility. Of interest, the genome shows a large number of mobile elements, and considerable variation in terms of predicted genes present in comparison to related C. difficile strains. The authors suggest this may be a mechanism for evolution and acquisition of factors that allow adaptation to the environment of the human gut, and may be associated with pathogen virulence or drug resistance.