AUTHOR=Xanthopoulou Kyriaki , Urrutikoetxea-Gutiérrez Mikel , Vidal-Garcia Matxalen , Diaz de Tuesta del Arco José-Luis , Sánchez-Urtaza Sandra , Wille Julia , Seifert Harald , Higgins Paul G. , Gallego Lucía 

TITLE=First Report of New Delhi Metallo-β-Lactamase-6 (NDM-6) in a Clinical Acinetobacter baumannii Isolate From Northern Spain

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.589253

DOI=10.3389/fmicb.2020.589253

ISSN=1664-302X

ABSTRACT=<p>The objective of this study was the phenotypic and genotypic characterization of a carbapenem resistant <italic>Acinetobacter baumannii</italic> (CRAB) isolate. The isolate, recovered in Northern Spain in 2019, was identified by MALDI-TOF to the species level. Antimicrobial susceptibility testing was performed using the Phoenix BD NMIC-502 Panel, E-test, and broth microdilution methods. The presence of a metallo-<italic>β</italic>-lactamase (MBL) was verified by PCR and immunochromatographic assays. The genetic location of the MBL was confirmed using S1-pulsed-field gel electrophoresis (S1-PFGE) followed by Southern blot hybridization. Whole genome sequencing (WGS) was completed using the Miseq and MinION platforms, followed by core-genome MLST (cgMLST) and seven-locus MLST analysis. The CRAB was assigned ST85 (Pasteur scheme) and ST957 (Oxford scheme) representing international clone (IC) 9 and harbored the intrinsic <italic>β</italic>-lactamase OXA-94 with IS<italic>Aba1</italic> upstream of it, and the MBL <italic>bla</italic><sub>NDM-6</sub>. Hybridization experiments revealed that the <italic>bla</italic><sub>NDM-6</sub> was encoded on the chromosome. Using WGS the <italic>bla</italic><sub>NDM-6</sub> environment could be identified arranged in the following order: IS<italic>Aba14</italic>, <italic>aphA6</italic>, IS<italic>Aba125</italic>, <italic>bla</italic><sub>NDM-6</sub>, <italic>ble</italic><sub>MBL</sub>, <italic>trpF</italic>, <italic>dsbC</italic>, <italic>cutA</italic>, and IS<italic>Aba14</italic>. Downstream, a 10,462 bp duplication was identified, including a second copy of <italic>bla</italic><sub>NDM-6</sub> in the following genetic composition: IS<italic>Aba125</italic>, <italic>bla</italic><sub>NDM-6</sub>, <italic>ble</italic><sub>MBL</sub>, <italic>trpF</italic>, <italic>dsbC</italic>, <italic>cutA</italic>, and IS<italic>Aba14</italic>. To our knowledge, this is the first description of <italic>bla</italic><sub>NDM-6</sub> in <italic>A. baumannii</italic>. The MBL was present in two copies in the chromosome in a new genetic environment associated with IS elements highlighting the contribution of mobile genetic elements in the dissemination of this gene.</p>