carried by a hypervirulent with sequence type 29.

BACKGROUND

A carbapenem-resistant hypermucoviscous 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 between bacterial strains was tested using conjugation. 59 genome assemblies of ST29 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 and exhibited a high virulence in wax moth. This hypervirulent strain belongs to sequence type 29 and carries , 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 IS region. Phylogenetic analysis of IncX3 plasmids revealed that although can be evolved from via point mutations within some IncX3 plasmids, most of -carrying IncX3 plasmids probably have acquired in multiple events.

CONCLUSIONS

In this study, we characterized a -positive hypervirulent of sequence type 29 in China. Our results highlight the need for active surveillance on this lineage of carbapenem-resistant .