We have sequenced, assembled and annotated the genome of Clostridium sordellii strain ATCC9714. Paraclostridium sordellii ATCC 9714

Clostridium sordellii is an anaerobic bacterium associated with rare but severe infections of man and animals. Human infections are associated with trauma, toxic shock and often-fatal gynaecological infections. Some strains are known to produce the large clostridial cytotoxins TcsH and TcsL, relatives of the cytotoxins found in C. difficile, C. novyi and C. perfringens. These 4 strains are part of a larger collection that reveal a diverse phylogenetic distribution. Although all strains originated from animal or clinical disease, only 5 strains contained cytotoxin genes: 4 strains contain tcsL alone and one strain contains tcsL and tcsH. Where present, tcsL and tcsH were localised on a pathogenicity locus, distinct to that present in C. difficile. In contrast to C. difficile, the C. sordellii tcsL and tcsH genes were always localised on plasmids, designated pCS1-1 in strain ATCC9714 and pCS1-3 in strain JGS6382. Phylogenetic analysis suggests gain and loss of entire toxigenic plasmids in addition to horizontal transfer of the pathogenicity locus. A high quality, annotated draft sequence of ATCC9714 reveals many putative virulence factors including genes for neuraminidase, phospholipase C and a cholesterol-dependent cytolysin sordellilysin that are highly conserved between all strains sequenced here. Our finding suggest that the cytotoxins may not be the primary virulence factors in the majority of infections, but that acquisition of these toxins may precipitate severe infection.