In silico analysis of sequenced strains of Clostridium difficile reveals a related set of conjugative transposons carrying a variety of accessory genes

The human gut pathogen Clostridium difficile contains many conjugative transposons that have an array of accessory genes. In the current study, recently sequenced genomes were analyzed to identify new putative conjugative transposons. Eleven new elements in 5 C. difficile strains were identified and all had a similar structure to the previously described elements CTn1, CTn5 and CTn7 in C. difficile strain 630. Each element identified did however contain a new set of accessory genes compared with those previously reported; including those predicted to encode ABC transporters, a toxin/antitoxin system and multiple antibiotic resistance genes.