New Delhi Metallo-β-Lactamase 1(NDM-1), the Dominant Carbapenemase Detected in Carbapenem-Resistant Enterobacter cloacae from Henan Province, China

PLoS One. 2015 Aug 11;10(8):e0135044. doi: 10.1371/journal.pone.0135044. eCollection 2015.

Abstract

The emergence of New Delhi metallo-β-lactamase 1 (NDM-1) has become established as a major public health threat and represents a new challenge in the treatment of infectious diseases. In this study, we report a high incidence and endemic spread of NDM-1-producing carbapenem-resistant Enterobacter cloacae isolates in Henan province, China. Eight (72.7%) out of eleven non-duplicated carbapenem-resistant E. cloacae isolates collected between June 2011 and May 2013 were identified as NDM-1 positive. The blaNDM-1 gene surrounded by an entire ISAba125 element and a bleomycin resistance gene bleMBL in these isolates were carried by diverse conjugatable plasmids (IncA/C, IncN, IncHI2 and untypeable) ranging from ~55 to ~360 kb. Molecular epidemiology analysis revealed that three NDM-1-producing E. cloacae belonged to the same multilocus sequence type (ST), ST120, two of which were classified as extensively drug-resistant (XDR) isolates susceptible only to tigecycline and colistin. The two XDR ST120 E. cloacae isolates co-harbored blaNDM-1, armA and fosA3 genes and could transfer resistance to carbapenems, fosfomycin and aminoglycosides simultaneously via a conjugation experiment. Our study demonstrated NDM-1 was the most prevalent metallo-β-lactamase (MBL) among carbapenem-resistant E.cloacae isolates and identified a potential endemic clone of ST120 in Henan province. These findings highlight the need for enhanced efforts to monitor the further spread of NDM-1 and XDR ST120 E. cloacae in this region.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Carbapenems / pharmacology*
  • China / epidemiology
  • Cluster Analysis
  • Electrophoresis, Gel, Pulsed-Field
  • Enterobacter cloacae / drug effects*
  • Enterobacter cloacae / genetics*
  • Enterobacteriaceae Infections / epidemiology
  • Enterobacteriaceae Infections / microbiology*
  • Humans
  • Microbial Sensitivity Tests
  • Multilocus Sequence Typing
  • Plasmids / genetics
  • beta-Lactam Resistance*
  • beta-Lactamases / genetics*

Substances

  • Anti-Bacterial Agents
  • Carbapenems
  • beta-Lactamases
  • beta-lactamase NDM-1

Grants and funding

Funding provided by Medical Science and Technique Foundation of Henan Province (Grant no. 112102310165 and no.201303046).