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ABSTRACT: Background
Colistin acts as the last line of defense against severe infections caused by carbapenem-resistant Enterobacteriaceae. Infections caused by extensively drug-resistant isolates coproducing MCR and carbapenemases have posed a serious public health concern.Purpose
In this study, we reported the first clinical colistin and carbapenem-resistant Enterobacter hormaechei isolate SCNJ07 coharboring bla NDM-1 and mcr-9 from a patient with bloodstream infection in China.Methods
Bacterial antimicrobial susceptibility testing was performed using the broth microdilution method. Conjugation assay was carried out to investigate the transferability of mcr-9 and bla NDM-1. Whole-genome sequencing of strain SCNJ07 was performed using an Illumina HiSeq system and the genetic characteristics of the mcr-9- and bla NDM-1-harboring plasmids were analyzed.Results
Conjugation assays revealed that both bla NDM-1 and mcr-9 genes could successfully transfer their resistance phenotype to Escherichia coli strain J53. Whole genome sequencing showed that SCNJ07 possessed an FIB36:FIIY4 type self-transmissible plasmid bearing bla NDM-1, which possessed high similarity to previously reported pRJF866 in China. mcr-9 was located on a ~28-kb self-transmissible plasmid pMCR-SCNJ07 with both IncHI2 and IncR replicons. Two copies of intact IS903 that bracketed a ~8-kb region containing the mcr-9 gene were identified in pMCR-SCNJ07. BLASTn analysis revealed that a number of mcr-9-positive plasmids have been around for a while among Enterobacteriaceae worldwide.Conclusion
This study reveals the likelihood of a wide dissemination of this newly identified colistin resistance gene mcr-9 among Enterobacteriaceae. Further surveillance is urgently needed to understand the prevalence and dissemination of mcr-9, thereby facilitating establishment of measures to control its spread.
SUBMITTER: Yuan Y
PROVIDER: S-EPMC6756836 | biostudies-literature | 2019
REPOSITORIES: biostudies-literature
Infection and drug resistance 20190919
<h4>Background</h4>Colistin acts as the last line of defense against severe infections caused by carbapenem-resistant <i>Enterobacteriaceae</i>. Infections caused by extensively drug-resistant isolates coproducing MCR and carbapenemases have posed a serious public health concern.<h4>Purpose</h4>In this study, we reported the first clinical colistin and carbapenem-resistant <i>Enterobacter hormaechei</i> isolate SCNJ07 coharboring <i>bla</i> <sub>NDM-1</sub> and <i>mcr-9</i> from a patient with b ...[more]