Genomic study of strains co-harboring and reveals a large multidrug-resistant plasmid encoding these carbapenemases in Brazil.

INTRODUCTION

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 . Our study focused on the antimicrobial susceptibility and genomic sequences related to plasmids from 12 clinical isolates of that carry both the blaOXA-58 and carbapenemase genes.

METHODS

Whole-genome sequencing with long-read technology was employed for the characterization of an A. baumannii plasmid that harbors the and blaNDM-1 genes. The location of the and genes was confirmed through Southern blot hybridization assays. Antimicrobial susceptibility tests were conducted, and molecular characterization was performed using PCR and PFGE.

RESULTS

Multilocus Sequence Typing analysis revealed considerable genetic diversity among and 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.

DISCUSSION

The propagation of and 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.