Bacteremia with a large clostridial toxin-negative, binary toxin-positive strain of Clostridium difficile.

Bacteremia caused by Clostridium difficile is rare. In this report, we describe a case of C. difficile bacteremia caused by an unusual strain of C. difficile. The isolate contained neither toxin A nor B genes, however, binary toxin genes were present (tcdA(-), tcdB(-), cdtA(+), cdtB(+)) and a 7.2-kb element unrelated to the PaLoc was found inserted within the PaLoc integration site. The clinical relevance of the isolate could not be determined.