Genomic characterisation of ST233 Pseudomonas aeruginosa co-producing KPC-2 and VIM-2 in Northeastern Brazil during the COVID-19 pandemic: Evidence of independent horizontal acquisition events.
BACKGROUND: Dual-carbapenemase-producing Pseudomonas aeruginosa poses a major therapeutic and epidemiological challenge worldwide, yet systematic data on KPC and VIM co-production in Brazil remain limited. The COVID-19 pandemic intensified antimicrobial use, a period temporally associated with increased carbapenemase detection globally. OBJECTIVES: To characterise the molecular epidemiology and resistance profiles of KPC and VIM co-producing P. aeruginosa isolates from Brazil (2019-2023). METHODS: Between 2019 and 2023, 1489 multidrug-resistant P. aeruginosa isolates were screened by multiplex PCR for carbapenemase-encoding genes. Co-producing isolates underwent pulsed-field gel electrophoresis (PFGE) for clonal profiling, followed by whole-genome sequencing (WGS) for high-resolution phylogenomic analysis. Antimicrobial susceptibility testing and plasmid characterisation using next-generation sequencing platforms were also performed. RESULTS: Forty-two isolates (2.8%) harboured both blaKPC-2 and blaVIM-2, with detection occurring exclusively between 2020 and 2023, temporally coinciding with the COVID-19 pandemic. PFGE identified eight distinct clonal groups, providing evidence for independent horizontal gene transfer (HGT) events, whilst WGS confirmed all isolates as the high-risk ST233 lineage. Chromosomally integrated blaVIM-2 within class 1 integrons predominated; 2 isolates carried dual chromosomal copies. Plasmid-borne blaKPC-2 was identified across heterogeneous replicons (43.3-430.1 kb), suggesting multiple independent acquisition events. All co-producing isolates displayed extensive drug resistance, retaining in vitro susceptibility only to cefiderocol and colistin. CONCLUSIONS: ST233 co-producing KPC and VIM, represents a high-risk resistance phenotype of epidemiological significance. Divergent genomic architectures suggest active horizontal dissemination across diverse genetic backgrounds rather than clonal expansion, highlighting the need for enhanced surveillance and infection control strategies.