The rapidly increasing prevalence of Klebsiella pneumoniae carbapenemase 2 (KPC-2)-producing bacteria has become a serious challenge to public health. Currently, the bla KPC- 2 gene is mainly disseminated through plasmids of different sizes and replicon types. However, the plasmids carrying the bla KPC- 2 gene have not been fully characterized. In this study, we report the complete genome sequences of two novel bla KPC- 2-harboring incompatibility group U (IncU) plasmids, pEC2341-KPC and pEC2547-KPC, from international high-risk clones of Escherichia coli isolated from Zhejiang, China. Two KPC-2-producing E. coli isolates (EC2341 and EC2547) were collected from clinical samples. Whole-genome sequencing (WGS) analysis indicated that EC2341 and EC2547 belonged to the ST410 and ST131 clones, respectively. S1-nuclease pulsed-field gel electrophoresis (S1-PFGE), Southern blot and conjugation experiments confirmed the presence of the bla KPC- 2 gene on the pEC2341-KPC plasmid and that this was a conjugative plasmid, while the bla KPC- 2 gene on the pEC2547-KPC plasmid was a non-conjugative plasmid. In addition, plasmid analysis further revealed that the two bla KPC- 2-harboring plasmids have a close evolutionary relationship. To the best of our knowledge, this is the first report of E. coli strains carrying the bla KPC- 2 gene on IncU plasmids. The emergence of the IncU-type bla KPC- 2-positive plasmid highlights further dissemination of bla KPC- 2 in Enterobacteriaceae. Therefore, effective measures should be taken immediately to prevent the spread of these bla KPC- 2 -positive plasmids.
Keywords: E. coli; IncU plasmid; KPC-2; high-risk clones; whole genome sequencing.
Copyright © 2021 Wu, Lu, Fan, Chen, Jin, Pan and Li.