Dataset Information

High Prevalence of bla NDM Variants Among Carbapenem-Resistant Escherichia coli in Northern Jiangsu Province, China.

ABSTRACT: The continuous emergence of carbapenem-resistant Escherichia coli (CRECO) presents a great challenge to public health. New Delhi metallo-lactamase (NDM) variants are widely disseminated in China, so the research on the prevalence and transmission of diverse bla NDM variants is urgently needed. In the present study, 54 CRECO isolates were collected from 1,185 Escherichia coli isolates in five hospitals in Northern Jiangsu Province, China from September 2015 to August 2016. Antimicrobial susceptibility tests, PCR detection of resistance determinants, multi-locus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) were performed to characterize these strains. Plasmid conjugation experiments were carried out to determine the transferability of resistant genes from selected isolates. PCR-based replicon typing (PBRT), S1 nuclease-PFGE, and Southern blotting were conducted for plasmid profiling. Carbapenemase genes were detectable in all CRECO isolates, among which thirty-one CRECO isolates were found to carry bla NDM-5 (54.7%), while, bla NDM-1, bla NDM-7, bla NDM-4, bla NDM-9, and bla KPC-2 were identified in 14, five, two, one, and one isolates, respectively. MLST results revealed 15 different STs and four new STs were first reported to be linked with NDM-producing isolates. PFGE typing showed that no more than two isolates with the same ST appeared to the same band pattern except three ST410 isolates. Twenty-six selected NDM-producing isolates were successfully transferred to E. coli J53 by conjugation experiments. Notably, 50.0% (13/26) of blaNDM variants were found to be carried by ~55 kb IncX3 plasmid. Our study reported a high prevalence of blaNDM variants, especially bla NDM-5, in Northern Jiangsu province, China. Diverse bla NDM variants were mainly carried by ~55 kb IncX3 plasmids, suggesting that the fast evolution and high transferability of this kind of plasmid promote the high prevalence of bla NDM variants. Therefore, large-scale surveillance and effective infection control measures are also urgently needed to prevent diverse bla NDM variants from becoming epidemic in the future.

SUBMITTER: Bi R

PROVIDER: S-EPMC6243109 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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High Prevalence of bla NDM Variants Among Carbapenem-Resistant Escherichia coli in Northern Jiangsu Province, China.

Bi Ruru R Kong Ziyan Z Qian Huimin H Jiang Fei F Kang Haiquan H Gu Bing B Ma Ping P

Frontiers in microbiology 20181113

The continuous emergence of carbapenem-resistant Escherichia coli (CRECO) presents a great challenge to public health. New Delhi metallo-lactamase (NDM) variants are widely disseminated in China, so the research on the prevalence and transmission of diverse bla NDM variants is urgently needed. In the present study, 54 CRECO isolates were collected from 1,185 Escherichia coli isolates in five hospitals in Northern Jiangsu Province, China from September 2015 to Augu ...[more]

PMID: 30483231

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Project description:New Delhi metallo-β-lactamases (NDMs), including at least 28 variants, are a rapidly emerging family of β-lactamases worldwide, with a variety of infections caused by NDM-positive strains usually associated with very poor prognosis and high mortality. NDMs are the most prevalent carbapenemases in Escherichia coli (E. coli) worldwide, especially in China. The vast majority of bla NDM cases occur on plasmids, which play a vital role in the dissemination of bla NDM. To systematically explore the relationships between plasmids and bla NDM genes in E. coli and obtain an overall picture of the conjugative and mobilizable bla NDM-positive plasmids, we analyzed the variants of bla NDM, replicon types, phylogenetic patterns, conjugative transfer modules, host STs, and geographical distributions of 114 bla NDM-positive plasmids, which were selected from 3786 plasmids from 1346 complete whole genomes of E. coli from the GenBank database. We also established links among the characteristics of bla NDM-positive plasmids in E. coli. Eight variants of bla NDM were found among the 114 bla NDM-positive plasmids, with bla NDM - 5 (74 bla NDM - 5 genes in 73 plasmids), and bla NDM - 1 (31 bla NDM - 1 genes in 28 plasmids) being the most dominant. The variant bla NDM - 5 was mainly carried by the IncX3 plasmids and IncF plasmids in E. coli, the former were mainly geographically distributed in East Asia (especially in China) and the United States, and the latter were widely distributed worldwide. IncC plasmids were observed to be the predominant carriers of bla NDM - 1 genes in E. coli, which were mainly geographically distributed in the United States and China. Other bla NDM - 1-carrying plasmids also included IncM2, IncN2, and IncHI1. Moreover, the overall picture of the conjugative and mobilizable bla NDM-positive plasmids in E. coli was described in our study. Our findings enhance our understanding of the genetic diversity and characteristics of bla NDM-positive plasmids in in E. coli.

Project description:BackgroundAntibiotics exert an outstanding selective pressure on bacteria, forcing their chromosomal gene mutations and drug resistance genes to spread. The objective of this study is to evaluate the expression of the New Delhi Metallo-β-Lactamase-1 gene (blaNDM-1) in the clinical isolate (Klebsiella pneumoniae TH-P12158), transformant strains Escherichia coli BL21 (DE3)-blaNDM-1, and Escherichia coli DH5α- blaNDM-1 when exposed to imipenem.Methodsβ-Lactamase genes (blaSHV, blaTEM-1, blaCTX-M-9, blaIMP, blaNDM-1, blaKPC, blaOXA, blaGES, and blaDHA) from randomly selected carbapenems-sensitive K.pneumoniae (n = 20) and E.coli (n = 20) strains were amplified by PCR. The recombinant plasmid of pET-28a harboring blaNDM-1 was transformed into E.coli BL21 (DE3) and E.coli DH5α by electroporation. The resistance phenotype and higher blaNDM-1 expression in K.pneumoniae TH-P12158, transformant E.coli BL21 (DE3)-blaNDM-1, and E.coli DH5α-blaNDM-1 were observed when exposed to imipenem with grade increasing, decreasing, and canceling doses, respectively.ResultsAfter being exposed to different doses of imipenem, the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of antimicrobial drugs and blaNDM-1 expression of strains increased, which was positively correlated with doses of imipenem. On the contrary, with the decrease or cancellation of imipenem doses, the blaNDM-1 expression was deteriorated, while the MIC and MBC values remained relatively stable. These results demonstrated that low doses of imipenem (˂MIC) could press blaNDM-1 positive strains producing stable drug resistance memory and altered blaNDM-1 expression.ConclusionsLow doses of imipenem could press blaNDM-1 positive strains producing sustained resistance memory and altered blaNDM-1 expression. In particular, the positive correlation between the resistance genes expression and antibiotics exposure shows promising guiding significance for clinical medication.

Dataset Information

High Prevalence of bla NDM Variants Among Carbapenem-Resistant Escherichia coli in Northern Jiangsu Province, China.

Publications

High Prevalence of <i>bla</i> <sub>NDM</sub> Variants Among Carbapenem-Resistant <i>Escherichia coli</i> in Northern Jiangsu Province, China.

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