Clostridium difficile plasmid isolation as an epidemiologic tool.

A large hospital outbreak of Clostridium difficile diarrhea at the Minneapolis Veterans Administration Medical Center (MVAMC) was studied by plasmid profile typing. Plasmids were obtained from 30 (37%) of 82 clinical isolates from MVAMC patients and 10 (67%) of 15 non-MVAMC isolates. While bacteriophage plus bacteriocin typing and polyacrylamide gel electrophoresis (PAGE) plus bacterial agglutination typing proved more universally applicable, plasmid profiles may be useful for tracing isolated epidemic outbreaks, reinfections and relapses caused by plasmid-bearing strains.