Novel use of toxigenic gene analysis for the identification of clostridium species

Abstract

Introduction 16S rRNA polymerase chain reaction (PCR) can result in accurate identification of many bacteria, but is not helpful in non-sterile specimens. We postulated specific toxin genes critically important in disease pathogenesis as alternative organism-specific targets in Clostridium perfringens, C. septicum and C. sordellii. We tested this theory using a 10-year single-institution Clostridium spp. bacteraemia series to investigate if there is any relatedness of presence of toxin genes to speciation of organism. Results Of 52 incident cases of blood cultures positive with Clostridium spp., there were 30 C. perfringens, six C. septicum and one C sordellii identified by 16S rRNA PCR. All 30 C. perfringens tested positive for plc genes by PCR, whilst two control isolates of C. septicum tested negative. All six C. septicum were also positive for csa gene, whilst the control C. sordellii did not produce a band. The single C. sordellii isolate tested did not generate a product specific for the tcsL or tcsH gene, the two major virulence determinants of this bacterium, but did result in an expected 450 bp sdlO fragment. Summary Toxigenic gene analysis can potentially be used to identify limited but important species of Clostridia when specific syndromes and aetiologies are suspected. Further work needs to be undertaken to further proof this.