An Epidemic, Toxin Gene–Variant Strain of Clostridium difficile

Recent reports suggest that the rate and severity of Clostridium difficile-associated disease in the United States are increasing and that the increase may be associated with the emergence of a new strain of C. difficile with increased virulence, resistance, or both.

A total of 187 C. difficile isolates were collected from eight health care facilities in six states (Georgia, Illinois, Maine, New Jersey, Oregon, and Pennsylvania) in which outbreaks of C. difficile-associated disease had occurred between 2000 and 2003. The isolates were characterized by restriction-endonuclease analysis (REA), pulsed-field gel electrophoresis (PFGE), and toxinotyping, and the results were compared with those from a database of more than 6000 isolates obtained before 2001. The polymerase chain reaction was used to detect the recently described binary toxin CDT and a deletion in the pathogenicity locus gene, tcdC, that might result in increased production of toxins A and B.