Genetic diversity and evolution of the virulence plasmids encoding aerobactin and salmochelin in <i>Klebsiella pneumoniae</i>

Abstract

Virulence plasmids of hypervirulent <i>Klebsiella pneumoniae</i> (hvKp) have the potential to transfer to drug-resistant strains or integrate with other plasmids, facilitating the genome evolution of threatening pathogens. We conducted an in-depth analysis of the publicly available 156 complete genome sequences of hvKp together with a multi-region clinical cohort of 171 hvKp strains from China to provide evidence for the virulence plasmid evolution. Virulence plasmids were frequently detected in the ST23 and ST11 <i>K. pneumoniae</i> strains. Multidrug-resistant hvKp (MDR-hvKp) occupied a large proportion of hvKp, and the coexistence of virulence and resistance plasmids may be the major cause. Virulence plasmids commonly possessed multiple replicons, of which IncFIB_K was the most prevalent (84.6%). We identified 49 IncFIB_K alleles among 583 IncFIB_K plasmids, and they could be divided into Clades I, II, and III. We further observed that conjugative and non-conjugative virulence plasmids could be distinguished by IncFIB_K genetic diversity, and IncFIB_K subtyping could also indirectly indicate a chimeric preference of conjugative virulence plasmids. On this basis, we developed an open-access web tool called <i>KpVR</i> for IncFIB_K subtyping. In conclusion, the genetic diversity of IncFIB_K virulence plasmids could be used for tracking the evolution of virulence plasmids, and further preventing the emergence of MDR-hvKp strains.