Epidemiological characteristics of carbapenem-resistant Enterobacteriaceae collected from 17 hospitals in Nanjing district of China

Antimicrob Resist Infect Control. 2020 Jan 13;9(1):15. doi: 10.1186/s13756-019-0674-4. eCollection 2020.

Abstract

Objective: In total, 97 carbapenem-resistant Enterobacteriaceae (CRE) were collected from 17 hospitals located in Nanjing, Southeast China, and analyzed for epidemiological characteristics.

Methods: Antimicrobial susceptibility was determined; followed by determination of the prevalence of resistance determinants, including extended-spectrum β-lactamase (ESBLs), plasmid-mediated AmpC enzyme (pAmpCs), plasmid-mediated quinolone resistance genes (PMQRs), fosfomycin resistance gene and exogenously acquired 16S rRNA methyltransferase (16S-RMTase) using PCR and DNA sequencing. The sequence types (STs) of CRE were determined by multi-locus sequence typing (MLST). The plasmid profiles were detected by PCR-based replicon typing (PBRT).

Results: All the CRE strains displayed high MIC50 and MIC90 for nearly all clinical available antibiotics, except for aztreonam/avibactam, minocycline, ceftazidime/avibactam, tigecycline, and colistin. KPC-2 (79.4%) and NDM (19.6%) were the main carbapenemases, CTX-M (76.3%) and SHV (60.8%) were the predominant ESBLs. In addition, oqxAB (70.1%) and qnr (63.9%) were the major PMQRs; rmtB (47.4%) was the main 16S-RMTase; fosA (76.3%) and fosA3 (37.1%) were the fosfomycin resistance gene. PBRT analysis showed presence of IncR (66.0%) and IncFII (64.9%) replicon types in the majority of the isolates, followed by IncFIB (46.4%) and IncX3 (16.5%). The IncFII and IncR replicon-types were found mainly in K. pneumoniae (68.8%), whereas the IncX3 replicons dominated in E. coli isolates (100.0%). The three dominating MLST-types ST11, ST15 and ST268 comprised 68.0% of the 77 K. pneumoniae. Seven distinct STs were identified among 8 E. coli.

Conclusions: The treatment for infections caused by CRE isolates is challenged by the presence of multiple resistance determinants and plasmid replicons. Our results highlighted the expansion of blaKPC-2 carrying K. pneumoniae ST11, the new emergency of single blaNDM-5 carrying K. oxytoca ST36, as well as blaIMP-4 and blaNDM-1 co-carrying E. cloacae ST418, which alert us on the urgency for antimicrobial resistant surveillance, to prevent dissemination of these highly transmissible and dangerous lineages.

Keywords: CRE; Carbapenemase; Klebsiella pneumoniae; Plasmid replicon; Sequence type.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Bacterial Proteins / genetics
  • Bacterial Typing Techniques / methods*
  • Carbapenem-Resistant Enterobacteriaceae / classification*
  • Carbapenem-Resistant Enterobacteriaceae / genetics
  • Carbapenem-Resistant Enterobacteriaceae / isolation & purification
  • China
  • Drug Resistance, Multiple, Bacterial
  • Hospitals
  • Humans
  • Klebsiella Infections / epidemiology*
  • Klebsiella Infections / microbiology
  • Microbial Sensitivity Tests
  • Multilocus Sequence Typing / methods
  • Phylogeny
  • Plasmids / genetics
  • Sequence Analysis, DNA / methods*

Substances

  • Anti-Bacterial Agents
  • Bacterial Proteins