Purpose: We aimed to characterize a novel bla_NDM-5 and bla_KPC-2 co-carrying hybrid plasmid from a clinical carbapenem-resistant Klebsiella pneumoniae (CRKP) strain.
Methods: Antimicrobial susceptibility was determined by the broth microdilution method. Plasmid size and localization were estimated using S1 nuclease pulsed-field gel electrophoresis (S1-PFGE) and Southern blotting. Plasmid transfer ability was evaluated by conjugation experiments. Whole genome sequencing (WGS) was performed using Illumina NovaSeq6000 and Oxford Nanopore MinION platforms. Genomic characteristics were analyzed using bioinformatics methods.
Results: Strain ZY27320 was a multidrug-resistant (MDR) clinical ST11 K. pneumoniae strain that confers high-level resistance to carbapenems (meropenem, MIC 128 mg/L; imipenem, MIC 64 mg/L) and ceftazidime/avibactam (MIC > 128/4 mg/L). Both S1-PFGE–Southern blotting and whole genome sequencing revealed that the carbapenemase genes bla_KPC-2 and bla_NDM-5 were carried by the same IncFII_pHN7A8:IncR:IncN hybrid plasmid (pKPC2_NDM5). Conjugation experiments indicated that pKPC2_NDM5 was a non-conjugative plasmid.
Conclusion: This is the first report of a hybrid plasmid carrying both carbapenemase genes bla_NDM-5 and bla_KPC-2 in a clinical K. pneumoniae ST11 isolate that confers resistance to both ceftazidime/avibactam and carbapenems, thereby presenting a serious threat to treatment in clinical practice.

Keywords: bla_NDM-5, bla_KPC-2, Klebsiella pneumoniae, hybrid plasmid, IS 26