International typing study of toxin A-negative, toxin B-positive Clostridium difficile variants.

Clinically important strains of Clostridium difficile that do not produce toxin A but produce toxin B and are cytotoxic (A(-)/B(+)) have been reported from multiple countries. In order to compare the relatedness of these strains, we typed 23 A(-)/B(+) C. difficile isolates from the United Kingdom (6 isolates), Belgium (11 isolates), and the United States (6 isolates) by three well-described typing methods. Restriction endonuclease analysis (REA), PCR ribotyping, and serogrouping differentiated 11, 4, and 3 different strain types, respectively. Twenty-one of the 23 A(-)/B(+) variants had a 1.8-... Mehr ...