Molecular characterization of toxin A-negative, toxin B-positive variant strains of Clostridium difficile isolated in Korea

A−B+Clostridium difficile strains are prevalent in Korea. We performed pulsed-field gel electrophoresis (PFGE), polymerase chain reaction ribotyping, and toxinotyping in 82 A−B+ clinical isolates in Korea. PFGE showed highest discriminatory capability among the 3 methods. By PFGE, persistence of a clone was found, suggesting this clone has adapted to the hospital environment.