Anin silicosurvey ofClostridioides difficileextrachromosomal elements
AbstractThe gram-positive enteropathogenClostridioides difficileis the major cause of healthcare associated diarrhoea and is also an important cause of community-acquired infectious diarrhoea. Considering the burden of the disease, many studies have employed whole genome sequencing to identify factors that contribute to virulence and pathogenesis. Though extrachromosomal elements such as plasmids are important for these processes in other bacteria, the few characterized plasmids ofC. difficilehave no relevant functions assigned and no systematic identification of plasmids has been carried out to date. Here, we perform anin silicoanalysis of publicly available sequence data, to show that ∼13% of allC. difficilestrains contain extrachromosomal elements, with 1-6 elements per strain. Our approach identifies known plasmids (e.g. pCD6, pCD630 and cloning plasmids) and 6 novel putative plasmid families. Our study shows that plasmids are abundant and may encode functions that are relevant forC. difficilephysiology. The newly identified plasmids may also form the basis for the construction of novel cloning plasmids forC. difficilethat are compatible with existing tools.RepositoriesThe assembled circular type plasmids have been deposited at the European Nucleotide Archive (ENA) under accession numbers ERZ940801 and ERZ940803-ERZ940808.