Dissemination of Carbapenemases (KPC, NDM, OXA-48, IMP, and VIM) Among Carbapenem-ResistantEnterobacteriaceaeIsolated From Adult and Children Patients in China

This study aimed to investigate the dissemination and characteristics ofbla(KPC),bla(NDM),bla(OXA-48-like),bla(IMP), andbla(VIM)among the carbapenem-resistantEnterobacteriaceae(CRE) strains isolated from adult and children patients. A total of 935 non-duplicate CRE strains were collected from 36 hospitals in 24 provinces or cities across China from 2016 to 2018. Antimicrobial susceptibility testing was performed by broth microdilution method and carbapenemase genesbla(KPC),bla(NDM),bla(OXA-48-like),bla(IMP), andbla(VIM)were screened by PCR and confirmed by DNA sequencing. Overall, carbapenemases were produced in 97.4% (911/935) of CRE strains, including KPC-2 (51.6%, 482/935), NDM (35.7%, 334/935), and OXA-48-like carbapenemases (7.3%, 68/935). Overall, the most prevalent carbapenemase gene wasbla(KPC-2)amongKlebsiella pneumoniae(64.6%, 457/709) and the CRE strains isolated from adult patients (70.3%, 307/437), andbla(NDM)amongEscherichia coli(96.0%, 143/149) and the CRE strains from children (49.0%, 247/498). Thebla(OXA-232)-positive carbapenem-resistantK. pneumoniae(9.3%, 66/709) were all isolated from children. Sixteen strains were positive forbla(IMP)and 9 strains produced multiple carbapenemases. No strain was positive forbla(VIM). Most of the CRE strains (>90%) were resistant to cephalosporins and carbapenems, more than half (>50%) were resistant to aminoglycosides and fluoroquinolones, but the majority (95.8 and 98.4%) were susceptible to polymyxin B and tigecycline. Ceftazidime-avibactam showed excellentin vitroactivity againstbla(KPC-2)andbla(OXA-48-like)positive strains (100% susceptible). In China, KPC-2, NDM, and OXA-48-like carbapenemases were predominant among CRE clinical isolates. The most prevalent carbapenemase gene wasbla(KPC-2)amongK. pneumoniaeisolates from adult patients, andbla(NDM)amongE. coliisolates from children.