Dissemination of NDM-1-Producing Enterobacteriaceae Mediated by the IncX3-Type Plasmid.

Qing Yang,Yunsong Yu,Ying Fu,Xiaoxing Du,Lanfang Fang,Yuqin Shen,Yung-Fu Chang

doi:10.1371/journal.pone.0129454

Qing Yang, Yunsong Yu + Show 5 more

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https://doi.org/10.1371/journal.pone.0129454

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Journal: PloS one	Publication Date: Jun 5, 2015
Citations: 37	License type: CC BY 4.0

Affiliation: Zhejiang University, Sir Run Run Shaw Hospital

Abstract

The emergence and spread of NDM-1-producing Enterobacteriaceae have resulted in a worldwide public health risk that has affected some provinces of China. China is an exceptionally large country, and there is a crucial need to investigate the epidemic of bla NDM-1-positive Enterobacteriaceae in our province. A total of 186 carbapenem-resistant Enterobacteriaceae isolates (CRE) were collected in a grade-3 hospital in Zhejiang province. Carbapenem-resistant genes, including bla KPC, bla IMP, bla VIM, bla OXA-48 and bla NDM-1 were screened and sequenced. Ninety isolates were identified as harboring the bla KPC-2 genes, and five bla NDM-1-positive isolates were uncovered. XbaI-PFGE revealed that three bla NDM-1-positive K. pneumoniae isolates belonged to two different clones. S1-PFGE and southern blot suggested that the bla NDM-1 genes were located on IncX3-type plasmids with two different sizes ranging from 33.3 to 54.7 kb (n=4) and 104.5 to 138.9 kb (n=1), respectively, all of which could easily transfer to Escherichia coli by conjugation and electrotransformation. The high-throughput sequencing of two plasmids was performed leading to the identification of a smaller 54-kb plasmid, which had high sequence similarity with a previously reported pCFNDM-CN, and a larger plasmid in which only a 7.8-kb sequence of a common gene environment around bla NDM-1 (bla NDM-1-trpF- dsbC-cutA1-groEL-ΔInsE,) was detected. PCR mapping and sequencing demonstrated that four smaller bla NDM-1 plasmids contained a common gene environment around bla NDM-1 (IS5-bla NDM-1-trpF- dsbC-cutA1-groEL). We monitored the CRE epidemic in our hospital and determined that KPC-2 carbapenemase was a major risk to patient health and the IncX3-type plasmid played a vital role in the spread of the bla NDM-1 gene among the CRE.

Highlights

Over the past ten years, carbapenemase-producing Enterobacteriaceae have disseminated rapidly throughout the world, posing an urgent threat to public health [1]
We further investigated the genomic characteristics of blaNDM-1-positive Enterobacteriaceae
Our results suggested that the blaNDM-1 genes were located on an IncX3-type plasmid and presented a similar genetic sequence around the blaNDM-1, which indicated the potential threat in China of carbapenem-resistant Enterobacteriaceae isolates (CRE) induced by the IncX3 plasmid encoding NDM-1 carbapenemase in Zhejiang

Summary

Introduction

Over the past ten years, carbapenemase-producing Enterobacteriaceae have disseminated rapidly throughout the world, posing an urgent threat to public health [1]. NDM-1 (New Delhi metallo-β-lactamase-1), one of the most serious carbapenemases, was first identified in Klebsiella pneumoniae and Escherichia coli in 2009, as NDM-1-producing Enterobacteriaceae rapidly disseminated, creating a global health crisis [2,3]. In China, Ho et al first reported the emergence of blaNDM-1-positive E. coli, which was isolated from a one-year-old infant and his mother [4]. At the beginning of the epidemic, most of the strains were isolated from stool samples, which suggested that intestinal colonization had occurred [5]. The epidemic has been reported to contribute to the active transmission of serious infectious diseases [8]

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