Variations in lethal toxin and cholesterol-dependent cytolysin production correspond to differences in cytotoxicity among strains of Clostridium sordellii

Clostridium sordellii is an emerging human pathogen and frequent contaminant of cadaver-derived tissue transplant material. Herein, we provide data suggesting the potential for severe C. sordellii-associated disease may be dictated by whether the specific strain produces lethal toxin (TcsL) or sordellilysin (SDL), a cholesterol-dependent cytolysin. The virulence factor profiles of 14 C. sordellii isolates were determined, and culture supernatant from six of the isolates was found to be cytotoxic to mammalian cells; yet, only one of these strains conferred cytotoxicity via production of TcsL. Cytotoxicity of TcsL- strains correlated with the production of sordellilysin, which was also recognized by an antiperfringolysin O antibody. However, supernatant from TcsL+, SDL- strains demonstrated a lower LD50 relative to TcsL-, SDL+ strains, suggesting the potential for severe C. sordellii-associated disease may be determined by the particular strain colonizing the host.