Background: Carbapenem-resistant Enterobacterales (CRE) are rapidly increasing worldwide in last two decades and lead few antibiotics for treatment. The molecular epidemiology of CRE in China was investigated to provide basis for clinical rational use of antibiotics and prevent its spread.
Methods: All CRE isolates in this study were collected from 11 hospitals from October 2015 to July 2018. The isolates were subjected to antimicrobial susceptibility tests, PCR molecular identification, pulsed-field gel electrophoresis, and multilocus sequence typing.
Results: Among the 399 CRE isolates, 51.6% (206/399) harbored carbapenemase genes. Three carbapenemase genes were detected, namely bla _KPC-2, bla _NDM-1, and bla _IMP at rates of 29.8% (119/399), 17.5% (70/399), and 4.0% (16/399), respectively. In Klebsiella pneumoniae  (350) and Escherichia coli  (26), bla _KPC-2 (33.4%, 117/350) and bla _NDM-1 (61.5%, 16/26) were the predominant genes. The most common genes in the CRE isolates were bla _KPC (85.5%) and bla _NDM-1 (76.5%) from adults and children, respectively. Particularly, ST11 K. pneumoniae  with bla _KPC-2 harbored by IncFII plasmids were distributed in both general and primary hospitals, suggesting a clonal transmission pattern at these sites. In addition, the clonal distribution of ST2407 K. pneumoniae  with bla _NDM-1 located on IncX3 plasmids and bla _IMP-38-positive ST307 K. pneumoniae  were detected in a children’s hospital.
Conclusion: The distribution of carbapenemase genes differed among strains and age groups. Multiple carbapenemase genes in the CRE strains were clonally disseminated in the tested regions mediated by multiple plasmids. Therefore, CRE monitoring should be increased and measures should be adopted to prevent its transmission.
Keywords: carbapenem-resistant Enterobacterales, bla _KPC-2, bla _NDM-1, bla _IMP, IncFII, ST11