AUTHOR=Rodrigues Daiana Cristina Silva , Silveira Melise Chaves , Pribul Bruno Rocha , Karam Bruna Ribeiro Sued , Picão Renata Cristina , Kraychete Gabriela Bergiante , Pereira Felicidade Mota , de Lima Rildo Mendes , de Souza Antonio Kleber Gomes , Leão Robson Souza , Marques Elizabeth Andrade , Rocha-de-Souza Cláudio Marcos , Carvalho-Assef Ana Paula D'Alincourt 

TITLE=Genomic study of Acinetobacter baumannii strains co-harboring blaOXA-58 and blaNDM-1 reveals a large multidrug-resistant plasmid encoding these carbapenemases in Brazil

JOURNAL=Frontiers in Microbiology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1439373

DOI=10.3389/fmicb.2024.1439373

ISSN=1664-302X

ABSTRACT=<sec><title>Introduction</title><p><italic>Acinetobacter baumannii</italic> contributes significantly to the global issue of multidrug-resistant (MDR) nosocomial infections. Often, these strains demonstrate resistance to carbapenems (MDR-CRAB), the first-line treatment for infections instigated by MDR <italic>A. baumannii</italic>. Our study focused on the antimicrobial susceptibility and genomic sequences related to plasmids from 12 clinical isolates of <italic>A. baumannii</italic> that carry both the blaOXA-58 and <italic>bla</italic><sub>NDM-1</sub> carbapenemase genes.</p></sec><sec><title>Methods</title><p>Whole-genome sequencing with long-read technology was employed for the characterization of an A. baumannii plasmid that harbors the <italic>bla</italic><sub>OXA-58</sub> and blaNDM-1 genes. The location of the <italic>bla</italic><sub>OXA-58</sub> and <italic>bla</italic><sub>NDM-1</sub> genes was confirmed through Southern blot hybridization assays. Antimicrobial susceptibility tests were conducted, and molecular characterization was performed using PCR and PFGE.</p></sec><sec><title>Results</title><p>Multilocus Sequence Typing analysis revealed considerable genetic diversity among <italic>bla</italic><sub>OXA-58</sub> and <italic>bla</italic><sub>NDM-1</sub> positive strains in Brazil. It was confirmed that these genes were located on a plasmid larger than 300 kb in isolates from the same hospital, which also carry other antimicrobial resistance genes. Different genetic contexts were observed for the co-occurrence of these carbapenemase-encoding genes in Brazilian strains.</p></sec><sec><title>Discussion</title><p>The propagation of <italic>bla</italic><sub>OXA-58</sub> and <italic>bla</italic><sub>NDM-1</sub> genes on the same plasmid, which also carries other resistance determinants, could potentially lead to the emergence of bacterial strains resistant to multiple classes of antimicrobials. Therefore, the characterization of these strains is of paramount importance for monitoring resistance evolution, curbing their rapid global dissemination, averting outbreaks, and optimizing therapy.</p></sec>