Characterization of a hypervirulent multidrug-resistant ST23 Klebsiella pneumoniae carrying a blaCTX-M-24 IncFII plasmid and a pK2044-like plasmid.

OBJECTIVE

To characterise a multidrug-resistant hypervirulent Klebsiella pneumoniae (MDR-hvKp) strain (Kpn1693) isolated from the sputum of a 67-year-old male patient diagnosed as having bronchiectasis with infection in Northern China.

METHODS

Drug susceptibility testing was performed by broth microdilution method, and the hypervirulent phenotype of the strain was analysed by string test and a mice systemic infection model. The whole genome of Kpn1693 was sequenced using PacBio Sequel platform, de novo assembly was performed using SMRT Link v5.0.1 software and the GeneMarkS program was used to retrieve the related coding gene. Incompatibility types, virulence-associated genes and antimicrobial resistance genes were searched for using the PlasmidFinder database, virulence factors of pathogenic bacteria database (VFDB) and Comprehensive Antibiotic Research Database (CARD). The phylogenetic relationship of pKpn1693-CTXM with other IncFII plasmids carrying variants of MEGA X software.

RESULTS

The Kpn1693 strain showed resistance to multiple antimicrobials and a hypervirulent phenotype. Bioinformatic analysis revealed that Kpn1693 had a 5 331 308-bp-long chromosome (cKpn1693), and harboured two plasmids of 192 347 bp (pK2044-like virulent plasmid, IncHI1B/IncFIB, pKpn1693-Vir) and 70 307 bp (blaCTX-M-24-bearing IncFII plasmid IncFII, pKpn1693-CTXM).

CONCLUSION

We reported an MDR-hvKp strain with a blaCTX-M-24-carrying IncFII-type plasmid and a pK2044-like virulent plasmid, and this is the first report of a blaCTX-M-24-bearing IncFII plasmid carried by an MDR-hvKp.