Clostridium difficile is a spore-forming, anaerobic, Gram-positive bacillus responsible for 15 to 25% of cases of post-antibiotic diarrhea and more than 95% of cases of pseudomembranous colitis (PMC). Since 2003, outbreaks of severe forms of C. difficile infection (CDI) have been reported in Canada and the United States. These outbreaks are linked to the emergence and spread of a specific clone of C. difficile called 027 (in reference to its PCR-ribotyping profile) or NAP1(referring to its pulsed-field gel electrophoresis profile). The increased virulence of this clone is thought to be due to the overproduction of toxins A and B and/or the production of a third toxin called the binary toxin. It is also characterized by its resistance to erythromycin and the newer fluoroquinolones (moxifloxacin, levofloxacin). This clone has spread to Great Britain, Belgium, the Netherlands, and more recently to France, where it has been responsible for outbreaks, primarily in the Nord-Pas-de-Calais region. As of April 4, 2007, clone 027 was detected in 35 of the 41 reported cases of ICD in this region. This concerning trend requires increased vigilance in healthcare facilities to control the spread of this clone.