Klebsiella pneumoniae and members from the associated species complex (i.e. KpSC) are leading causes of healthcare-associated infections in clinical settings. They represent a significant public health threat due to rising rates of antimicrobial resistance (AMR), which is often linked to plasmid transmission. Outside of the hospital, some strains of K. pneumoniae with hypervirulent properties also cause invasive community-acquired infections. Hypervirulence and AMR have historically been segregated in non-overlapping populations but reports of ‘convergent’ AMR-virulent strains have become increasingly common in recent years and have been known to cause fatal outbreaks. Like AMR, genes associated with hypervirulence are also predominantly mobilised by plasmids. Plasmid transmission is therefore a significant driver of convergence (i.e. hypervirulent strain acquiring an AMR plasmid or strain with AMR acquiring a virulence plasmid), highlighting the need to monitor the movement of AMR and virulence plasmids in K. pneumoniae to detect emergent convergent clones.
Here, we screened a public and global dataset of 50,000 Klebsiella assemblies for AMR-virulence convergence in order to examine the frequency and nature of convergence. More specifically, we used this dataset to explore (i) whether there were particular clones that were overrepresented amongst the convergent population and have had multiple independent plasmid acquisitions giving rise to convergence, and (ii) the population of plasmids and plasmid diversity underpinning convergence. Insights from both of these key overarching questions are important for dissecting the host (i.e. clone) versus plasmid contributions to AMR and virulence convergence in K. pneumoniae, and refining surveillance strategies to target ‘higher risk’ clones and/or plasmids that contribute disproportionately to convergence.