Genomic analysis of carbapenem-resistant non-baumannii Acinetobacter harboring chromosomal blaOXA-23 or plasmid-mediated blaNDM-1, blaIMP-14, and blaOXA-58

Abstract

Introduction Carbapenem-resistant Acinetobacter species are among the top priority pathogens, posing a threat to public health in both hospital- and community-acquired settings. Notably, the prevalence of carbapenemase-producing non-baumanniiAcinetobacter (CP-NBA) has recently increased worldwide. Methods This study aimed to describe the molecular characteristics of non-baumannii Acinetobacter isolates with two or more carbapenemases in South Korea. Among 590 nonduplicated carbapenem-resistant Acinetobacter species collected from community hospitals in South Korea between 2022 and 2023, a total of 13 CP-NBA isolates were used in this study. Whole-genome sequencing and in silico molecular analysis were performed to characterize their genomic features. Results Of the thirteen CP-NBA isolates, nine (four A. nosocomialis, two A. pittii, two A. seifertii, and one A. bereziniae) carried chromosomal blaOXA-23 integrated within Tn2006 in AbaRs. In addition, two A. bereziniae isolates with Rep3-T25 plasmids carrying blaVIM-2 and blaOXA-58 and one A. bereziniae isolate with the Rep3-T25 plasmid carrying blaNDM-1 and blaOXA-58 were identified. Finally, one A. pittii isolate with a putative 289 kb plasmid carrying three carbapenemase genes, blaNDM-1, blaOXA-58, and blaIMP-14, lacking a replication origin gene was detected. Conclusion In conclusion, our study described the genomic structure of carbapenemase genes and related mobile genetic elements in 13 CP-NBA isolates. Although the carbapenemase genotypes are diverse, CP-NBA strains are still relatively rare in local clinics in South Korea. In particular, the blaIMP-14 gene was first identified in South Korea. These results suggest that the dissemination of CP-NBA isolates should be handled carefully in terms of transmission between bacterial strains in the clinical setting.