Multispecies emergence of dual bla_KPC/NDM carbapenemase-producing Enterobacterales recovered from invasive infections in Chile

Carbapenemase-producing carbapenem-resistant Enterobacterales (CP-CRE) represent a significant global threat. The emergence of dual CP-CRE is particularly alarming, as they can potentially compromise the efficacy of newer antibiotics, further decreasing therapeutic alternatives. Herein, we report the emergence of multiple species of CP-CRE recovered from invasive infections in Chile that simultaneously harbor bla_KPC and bla_NDM and provide an in-depth genomic characterization of these worrisome pathogens. We collected carbapenem-resistant Enterobacterales (CRE) isolates from invasive infections over a 4-year period, across 11 healthcare centers in Chile. Bacterial species and the presence of carbapenemase genes were confirmed using MALDI-TOF and PCR assays, respectively. Antimicrobial susceptibility testing was conducted through disk diffusion and broth microdilution methods. Dual CP-CRE isolates were subjected to short- and long-read whole genome sequencing to perform a detailed genomic characterization of the isolates and of the mobile genetic elements harboring the enzymes. From a total of 1,335 CRE isolates, we observed an increase in the prevalence of CP-CRE, from 11% in 2019 to 38% in 2022. A total of 11 dual CP-CRE isolates were recovered, all of them harboring bla_KPC and bla_NDM. Species corresponded to Escherichia coli (n = 6), Klebsiella pneumoniae (n = 2), Klebsiella oxytoca (n = 2), and Citrobacter freundii (n = 1). Dual CP-CRE isolates exhibited resistance to all tested β-lactams except for cefiderocol. The bla_KPC and bla_NDM encoding genes were located on independent plasmids. Platforms harboring bla_KPC were diverse and included IncN, IncF, and IncFIB plasmids. In contrast, bla_NDM-7 was only found on fairly conserved IncX3 plasmids. We report that a rapid increase of CP-CRE in Chile, alongside with the emergence of multiple bacterial species of CP-CRE co-harboring bla_KPC-2/3 and bla_NDM-7, underscores a critical public health challenge. Our data suggest that the dissemination of bla_NDM-7 was predominantly facilitated by IncX3 plasmids, whereas the spread of bla_KPC involved multiple plasmid backbones. Active surveillance and genomic monitoring are critical to inform public policy and curtail the spread of these highly resistant pathogens.