Using an Endogenous CRISPR-Cas System for Genome Editing in the Human Pathogen Clostridium difficile

Clostridium difficile represents today a real danger for human and animal health. It is the leading cause of diarrhea associated with health care in adults in industrialized countries. The incidence of these infections continues to increase, and this trend is accentuated by the general aging of the population. Many questions about the mechanisms contributing toC. difficile 's success inside the host remain unanswered. The set of genetic tools available for this pathogen is limited, and new developments are badly needed.C. difficile has developed efficient defense systems that are directed against foreign DNA and that could contribute to its survival in phage-rich gut communities. We show how one such defense system, named CRISPR-Cas, can be hijacked forC. difficile genome editing. Our results also show a great potential for the use of the CRISPR-Cas system for the development of new therapeutic strategies againstC. difficile infections.