Researchers have characterized a virulent strain of Clostridium difficile associated with outbreaks of severe illness in Canada and Europe and found clues to why this strain causes unusually severe disease (Warny et al. Lancet. 2005;366:1079-1084).
C difficile–associated disease, which primarily occurs as a complication of antibiotic therapy, results from the production of bacterial toxins A and B. When incidence and mortality due to nosocomial cases of the infection began to increase dramatically in Quebec in 2002, scientists from Canada, the United Kingdom, and the United States decided to investigate whether this increase was due to emergence of a strain that produced higher levels of the toxins than nonepidemic strains.
Stephenson J. Virulent. JAMA. 2005;294(19):2423. doi:10.1001/jama.294.19.2423-b