Abstract
This study aimed to investigate the dissemination and characteristics of bla(KPC), bla(NDM), bla(OXA-48-like) , bla(IMP), and bla(VIM) among the carbapenem-resistant Enterobacteriaceae (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 genes bla(KPC), bla(NDM), bla(OXA-48-like) , bla(IMP), and bla(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 was bla(KPC-2) among Klebsiella pneumoniae (64.6%, 457/709) and the CRE strains isolated from adult patients (70.3%, 307/437), and bla(NDM) among Escherichia coli (96.0%, 143/149) and the CRE strains from children (49.0%, 247/498). The bla(OXA-232)-positive carbapenem-resistant K. pneumoniae (9.3%, 66/709) were all isolated from children. Sixteen strains were positive for bla(IMP) and 9 strains produced multiple carbapenemases. No strain was positive for bla(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 excellent in vitro activity against bla(KPC-2) and bla(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 was bla(KPC-2) among K. pneumoniae isolates from adult patients, and bla(NDM) among E. coli isolates from children.