Phenotypic and Genotypic Characterization of Carbapenem-Resistant Enterobacteriaceae Recovered from a Single Hospital in China, 2013 to 2017

Objective: Carbapenem-resistant Enterobacteriaceae (CRE) have become an increasingly common cause of healthcare-related infections and present a serious challenge to clinical treatment. This study examined the phenotypic, genotypic characterization, clinical, and microbiological data of CRE in the Huizhou Municipal Central Hospital.Methods: We conducted a phenotypic susceptibility evaluation and whole genome sequence analysis for 52 CRE strains isolated from 37 patients and 2 medical device-related samples during 2013-2017 to characterize risk factors, antimicrobial resistance profiles, dominant clones and hospital transmission.Results: Long-term hospitalization, treatment time with antibiotics and use of invasive devices were linked to the risk of CRE infection. The carbapenem resistance genes (CRGs) we found included blaNDM (82.7%), blaIMP(19.2%) and blaKPC (3.8%), Escherichia coli (44.2%) and Klebsiella pneumoniae (44.2%) were the dominant species we identified, and the type of CRG carried by isolates was highly correlated with species. The coexistence of CRGs with a variety of other antibiotic resistance genes leads to an increased prevalence of high resistance levels for CRE to beta-lactams and other antibiotic classes such as aminoglycosides and fluoroquinolones. These isolates were sensitive only to colistin and tigecycline. In addition to this, we observed significantly genomic diversity of CRE isolates in this hospital. Importantly, we found that long-term transmission of multiple CRE clones had occurred at this hospital between various wards.Conclusion: Evaluating and improving the current infection control strategies may be necessary, and reducing nosocomial transmis-sion remains the primary control element for CRE infections in China.