Virulent Strain, but Clinical Virulence Remains to Be Determined at the Bedside

Clostridium difficile infection (CDI) is the major cause of nosocomial diarrhea, as-sociated with increased morbidity and mortality, prolonged duration of hospital admissions, and increased admission costs. In 2005, the first studies to describe severe epidemics associated with a single “hypervirulent ” strain emerged from the United States, Canada, and Europe [1–3]. Depending on themolecular typingmeth-od, this strain is most commonly known as polymerase chain reaction (PCR) ribo-type 027 (type 027), but also as North American pulsed-field type 1, restriction endonuclease analysis type BI, and toxi