Infectious Disease · Medical Literature
[Correspondence] Convergence of hypervirulence and multidrug resistance driven by plasmid hybridisation and insertion sequence-mediated chromosomal integration in Klebsiella pneumoniae
Abstract
The convergence of hypervirulence and multidrug resistance (MDR) traits in Klebsiella pneumoniae has dramatically accelerated over the past decade, highly challenging the health-care network.1 Current evidence suggests that the convergence is primarily driven by the acquisition of virulence plasmids by resistant strains and vice versa or by plasmid hybridisation. Although plasmid hybridisation has only been reported sporadically,2,3 a recent Article in The Lancet Microbe by Marjorie J Gibbon and colleagues revealed frequent hybridisation of cocirculating iuc3 plasmids and resistance plasmids in both health-care and community settings.
Clinical relevance
In carbapenem-resistant Klebsiella pneumoniae sequence type ST11 — the dominant clone in China — how frequently does convergence of hypervirulence and multidrug resistance occur, and what molecular mechanisms (plasmid hybridisation versus insertion sequence–mediated chromosomal integration) drive this convergence? __SNAPSHOT__ {"studyDesign":"Correspondence reporting a descriptive genomic epidemiology analysis (cross-sectional, observational) using national surveillance data and long-read sequencing","setting":"China; data derived from the national Blood culture and Resistance in Chinese Hospitals (BRICS) surveillance programme for bloodstream infections","sampleSize":"396 iuc-positive carbapenem-resistant K. pneumoniae ST11 (CRKP-ST11) isolates from BRICS (iuc1 n=389, iuc3 n=3, iuc5 n=4); long-read sequencing performed on 33 isolates; Southern blot confirmation applied to 61 genomes identified by BLAST screening","population":"Carbapenem-resistant K. pneumoniae bloodstream isolates belonging to the clinically dominant ST11 clone collected through national surveillance in China; iuc-positive subset only","intervention":"Whole-genome and long-read (long-read hybrid assembly) sequencing to characterise plasmid structure, identify hybrid plasmids co-harboring KPC-2 carbapenem-resistance and virulence loci (rmpA/A2, iucABCD-iutA), and detect insertion sequence (IS)–mediated chromosomal integration of virulence loci","comparator":"Not applicable (single-arm genomic surveillance study)","primaryOutcome":"Frequency and mechanisms of convergence between hypervirulence and multidrug resistance in CRKP-ST11: (1) detection of KPC-2/rmpA/A2-positive hybrid plasmids; (2) detection of chromosomal integration of virulence loci mediated by insertion sequences","followUp":"Not reported (cross-sectional surveillance dataset)","fundingSource":"Not reported in the abstract or correspondence text available"}
Key findings
Among 33 CRKP-ST11 isolates characterised by long-read sequencing, seven iuc1-positive plasmids carried antibiotic resistance genes, suggesting a high frequency of co-occurrence of resistance and virulence determinants on a single plasmid in ST11. BLAST screening against the remaining genomes using two confirmed hybrid plasmids (pVir-KP45147 and pVir-KP70059) identified 61 genomes with ≥90% coverage for hybrid plasmid sequences. Southern blotting with rmpA/A2 and blaKPC-2 probes confirmed 27 of these 61 genomes (44.3%, calculated) carry KPC-2/rmpA/A2-positive hybrid plasmids, highlighting convergence of carbapenem resistance and hypervirulence. In addition, chromosomal integration of virulence loci (rmpA/A2 and iucABCD-iutA) was detected in 3 of 33 long-read–sequenced genomes (9.1%, calculated), representing a secondary IS-mediated mechanism of genomic convergence. No clinical outcomes, NNT/NNH, p-values, or confidence intervals were reported in the correspondence abstract. The companion article by Gibbon et al. (Lancet Microbe 2026;7:101236), which prompted this correspondence, identified seven convergent K. pneumoniae plasmids in a Thai One-Health dataset (six from fresh markets, one from a neighbouring hospital), all arising through hybridisation of iuc3 plasmids and ESBL-encoding plasmids; none of the seven carried carbapenemase genes.
Practice implications
This correspondence establishes that convergence of hypervirulence and carbapenem resistance in the dominant Chinese CRKP-ST11 clone occurs through at least two distinct genomic mechanisms: (1) plasmid hybridisation resulting in a single plasmid carrying both blaKPC-2 and rmpA/A2 virulence determinants, confirmed in 27 genomically characterised bloodstream isolates; and (2) IS-mediated chromosomal integration of virulence loci, detected in 3 isolates. The findings extend the Gibbon et al. observation — that iuc3 plasmid hybridisation is frequent even outside healthcare settings — to a context of full carbapenem resistance (KPC-2), which was absent in the Thai-market convergent plasmids. The study does not establish clinical outcome data (mortality, morbidity, or treatment failure rates) attributable to convergent isolates, nor does it determine whether chromosomally integrated virulence loci are phenotypically expressed or are associated with a clinically hypervirulent phenotype. Results apply primarily to hospitalised Chinese patients with CRKP-ST11 bloodstream infections; generalisability to other sequence types, other geographic regions, or community-onset infections is not established. Importantly, the convergence of KPC-producing and hypervirulent traits within a single transferable plasmid raises the prospect of rapid horizontal dissemination of this dual-threat phenotype. Only an abstract and correspondence text were available for full appraisal; the full dataset, statistical methodology, and bioinformatic parameters are not reviewable, which limits certainty of interpretation. No recommendation for change in empirical antibiotic regimens can be derived from this study alone. __LIMITATIONS__ Correspondence format only — full methods, statistical analyses, and complete data tables are not available for critical appraisal,Cross-sectional design with no clinical outcomes (mortality, length of stay, treatment failure) reported; genomic convergence does not necessarily equate to clinically enhanced virulence,Restricted to iuc-positive CRKP-ST11 bloodstream isolates from Chinese national surveillance; findings may not generalise to other K. pneumoniae clonal lineages, other geographic settings, or non-bloodstream infection sources,Long-read sequencing performed on only 33 of 396 iuc-positive isolates; hybrid plasmid detection in the remaining isolates relied on short-read mapping/BLAST with a ≥90% coverage threshold, which may yield false positives (mitigated but not eliminated by Southern blotting),Southern blot confirmation applied to 61 genomes selected by BLAST screening; selection bias cannot be excluded if BLAST pre-screening systematically missed divergent hybrid variants,Chromosomal integration of virulence loci was detected in only 3 isolates — too few to characterise the prevalence, genomic context, or phenotypic consequences of this mechanism,Phenotypic hypervirulence (e.g., hypermucoviscosity, serum resistance, in vivo virulence) of confirmed hybrid-plasmid carriers was not assessed,Hybrid plasmids identified in the companion Gibbon et al. study carried ESBL genes but not carbapenemases, whereas those in this correspondence carry KPC-2; the epidemiological relationship and trajectory between these populations is uncertain,Funding source and potential conflicts of interest are not reported __BOTTOM_LINE_CATEGORY__ promising_but_preliminary __BOTTOM_LINE__ In Chinese CRKP-ST11 bloodstream isolates, convergence of KPC-2 carbapenem resistance and hypervirulence (rmpA/A2, iucABCD-iutA) on a single hybrid plasmid was confirmed in 27 of 61 screened genomes, with IS-mediated chromosomal virulence integration detected in 3 additional isolates, demonstrating that dual-threat strains are not rare within this clone. These findings reinforce the epidemiological urgency of routine genomic surveillance for convergent CRKP — particularly in high-endemic regions — but do not yet establish clinical outcome differences or mandate changes to empirical therapy. Until prospective outcome data are available, clinicians managing CRKP infections from high-prevalence settings should maintain a high index of suspicion for concurrent hypervirulence traits, particularly in the context of invasive or metastatic presentations.