AUTHOR=Le-Vo Hong-Ngoc , Tran Phuong Thi-Bich , Le Lien , Matsumoto Yuki , Motooka Daisuke , Nakamura Shota , Jones James W. , Iida Tetsuya , Cao Van 

TITLE=Complex Class 1 Integron in a Clinical Escherichia coli Strain From Vietnam Carrying Both mcr-1 and blaNDM–1

JOURNAL=Frontiers in Microbiology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2019.02472

DOI=10.3389/fmicb.2019.02472

ISSN=1664-302X

ABSTRACT=<p>The co-production of MCR and carbapenemase in <italic>Enterobacteriaceae</italic> has been previously reported. Here, we describe a clinical strain of <italic>Escherichia coli</italic> from Vietnam carrying both <italic>mcr-1</italic> and <italic>bla</italic><sub>NDM–1</sub>. Whole-genome sequencing showed that the genome of this strain consists of a 4,975,832-bp chromosome and four plasmids. The <italic>mcr-1</italic> and <italic>bla</italic><sub>NDM–1</sub> genes are located on IncI2 and IncA/C2-type plasmids, respectively. Genetic analysis revealed the presence of a multidrug-resistant region with the structure of a novel complex class 1 integron including a class 1 integron region bearing two 5′ conserved segments and one 3′ conserved segment and two complete structures of IS<italic>CR1</italic>. The complex integron contains aminoglycoside resistance genes <italic>aadA2</italic>, <italic>aadB</italic>, <italic>strA</italic>, <italic>strB</italic>, and <italic>aphA6</italic>, quinolone resistance gene <italic>qnrA1</italic>, extended-spectrum β-lactamase gene <italic>bla</italic><sub>OXA–</sub><sub>4</sub>, and a Tn<italic>125</italic>-like transposon bearing <italic>bla</italic><sub>NDM–1</sub>. In addition, the <italic>dfrA12</italic>-<italic>gcuF</italic>-<italic>aadA2</italic>-<italic>cmlA1</italic>-<italic>aadA1-qacH</italic> gene cassette array belonging to the <italic>sul3</italic>-type integron was also identified, but the region found downstream of the gene cassette array is the IS<italic>440</italic>-<italic>tet(M)</italic>-IS<italic>26</italic> element instead of the <italic>sul3</italic> gene. The results further support that <italic>Enterobacteriaceae</italic> isolates co-harboring <italic>mcr</italic> and <italic>bla</italic><sub>NDM</sub> are widely being distributed. The structural characteristics of the complex integron reveal that IS<italic>CR1</italic> elements play an important role in the mobilization of <italic>bla</italic><sub>NDM–1</sub> and the development of multidrug-resistant regions.</p>