bla(NDM-5) carried by a hypervirulent Klebsiella pneumoniae with sequence type 29

BACKGROUND: A carbapenem-resistant hypermucoviscous Klebsiella pneumoniae isolate was recovered from human sputum. METHODS: Whole genome sequencing of this isolate was carried out to reveal its clonal background, antimicrobial resistance determinants and virulence factors. Virulence assays were performed using wax moth larvae. The transfer of bla(NDM-5) between bacterial strains was tested using conjugation. 59 genome assemblies of ST29 K. pneumoniae and 230 IncX3 plasmids regardless of the carriage of resistance gene were employed for phylogenetic analysis, respectively. RESULTS: The strain carried a virulence plasmid pVir-SCNJ1 bearing the virulence gene rmpA and exhibited a high virulence in wax moth. This hypervirulent strain belongs to sequence type 29 and carries bla(NDM-5), which is located on a conjugative plasmid, designated pNDM5-SCNJ1, belonging to type IncX3. pNDM5-SCNJ1 was fully sequenced and shows high similarity with pNDM_MGR194, except some deletion inside the ISAba125 region. Phylogenetic analysis of IncX3 plasmids revealed that although bla(NDM-5) can be evolved from bla(NDM-1) via point mutations within some IncX3 plasmids, most of bla(NDM-5)-carrying IncX3 plasmids probably have acquired bla(NDM-5) in multiple events. CONCLUSIONS: In this study, we characterized a bla(NDM-5)-positive hypervirulent K. pneumoniae of sequence type 29 in China. Our results highlight the need for active surveillance on this lineage of carbapenem-resistant K. pneumoniae. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13756-019-0596-1) contains supplementary material, which is available to authorized users.