Carbapenem-resistant carrying or in the clinic: one-decade genomic epidemiology analysis.

Unlabelled: Carbapenem-resistant (CRMM) isolates, particularly those producing Klebsiella pneumoniae carbapenemase-2 (KPC-2) or New Delhi metallo-β-lactamase-1 (NDM-1), are increasingly being recognized as causative agents of nosocomial infections. However, systematic phylogeography and genetic characterization of these isolates worldwide are still lacking. Here, through seven years of surveillance of CRMM in a tertiary hospital, we analyzed the genomic characteristics of - or -positive CRMM isolates. Furthermore, we conducted a global genomic epidemiological study of spp. harboring or using the NCBI database over the past decade. By combining the timeline of isolate collection with the structural analysis of the plasmids, we traced the evolution of the IncL/M plasmid, which acquired the gene. Our findings indicate that horizontal transfer of Tn based on IS is crucial for the transmission of in CRMM isolates. Additionally, the Tn transposon appears to have played an important role in early plasmid-mediated dissemination of ; however, it has been surpassed in recent years by other elements, including IS and IS. In summary, through phylogeographic analysis of spp. globally, we elucidated their spatial-temporal distribution and revealed the evolutionary characteristics of KPC- or NDM-producing CRMM isolates as the predominant "epidemic" clone.

Importance: Currently, infections attributable to carbapenem-resistant (CRMM) isolates harboring or are on the rise, highlighting the increasing severity of acquired antimicrobial resistance. However, systematic phylogeographic and genetic characterization of these isolates worldwide is still lacking. In this study, we elucidated the spatial-temporal distribution and evolutionary trajectory of and genes within their core genetic environments. We emphasize the necessity of strengthening surveillance and controlling these organisms in clinical settings to prevent the generation of so-called "superbug" isolates.