Genetic diversity and evolution of the virulence plasmids encoding aerobactin and salmochelin in Klebsiella pneumoniae

Abstract

Virulence plasmids of hypervirulent Klebsiella pneumoniae (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 K. pneumoniae 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 KpVR 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.

Co-conjugation of Virulence Plasmid and KPC Plasmid in a Clinical Klebsiella pneumoniae Strain

“…These virulence plasmids lacked virulence genes rmpA and iroBCDN when compared to typical virulence plasmid pLVPK, which may affect the virulence potentials of these CRKP strains. However, 96.2% of the virulence plasmids in the GenBank carried iucA , while only 46.8% carried iroB ( Tian et al, 2021 ). The virulence effects and any benefits of the iro deletion remains to be studied.…”

Acquisition of the Conjugative Virulence Plasmid From a CG23 Hypervirulent Klebsiella pneumoniae Strain Enhances Bacterial Virulence

“…Conjugative virulence plasmids were possibly formed by the insertion of an aerobactin cluster into an IncFIB K /IncFII conjugative plasmid (Tian et al, 2021), and the composition of pK2606 is concordant with this observation. There are also some other reports concerning conjugative virulence plasmids.…”

“…The most common virulence plasmids acquired by CRKP strains are non-conjugative pK2044-like plasmids, but their mechanism of transfer is still uncertain. Our previous study identified some conjugative virulence plasmids encoding aerobactin genes in Klebsiella pneumoniae (Tian et al, 2021). Considering their potential for self-conjugation, it is essential to confirm the virulence of the host bacteria and their ability to transfer to other strains.…”

“…The emergence of hypervirulent and carbapenem-resistant Klebsiella pneumoniae has become a hot topic, and research is increasingly focused on the mechanism of transmission, but this currently remains unclear. The virulence plasmids acquired by ST11 carbapenem-resistant Klebsiella pneumoniae (CRKP) are commonly pK2044-like plasmids, which are considered nonconjugative (Smillie et al, 2010;Tian et al, 2021). According to several studies these virulence plasmids confer hypervirulence to other strains (Gu et al, 2018;Zhang et al, 2020).…”

“…Our earlier study provided a scheme to distinguish conjugative virulence plasmids from non-conjugative virulence plasmids by assessment of IncFIB K genetic diversity (Tian et al, 2021). However, the virulence level conferred by conjugative virulence plasmids needs to be further characterized.…”