Genomic virulence content of OXA-48-producing Klebsiella pneumoniae clinical isolates

In this study, we gathered information on the virulent content in non-outbreak, high-risk clones and other less common STs associated with the spread of OXA-48 -producing K. pneumoniae clinical isolates from The Netherlands (n=61) and Spain (n=53). We mostly observed multidrug resistant lineages, such as ST11, ST15, and ST405, and unassigned lineages, ST133 and ST192, acquiring accessory virulence factors, the siderophore yersiniabactin gene cluster and the genotoxin colibactin gene cluster for the latter two STs, via integrative conjugative elements (ICEKp). We only observed anecdotic cases in which K-serotypes associated with hypervirulence, K54 and K2, acquired a blaOXA-48 carbapenemase via plasmid. As previously described in this species, we observed a high diversity of K-serotypes and K- and O-antigens combinations, but some virulence gene clusters could be used as high-risk multidrug resistant clone markers. The fimbrial adhesin Kpi operon (KpiABCDEFG) was associated with ST14, ST15, and ST405 isolates, and the ferric uptake system kfuABC was associated with the same STs plus ST101 isolates. In addition, most isolates shared a chromosomally-encoded core of virulence factors, including the enterobactin gene cluster, fimbriae fim and mrk gene clusters, and urea metabolism genes (ureAD). Our results contribute towards understanding the pathogenicity of multidrug resistant K. pneumoniae lineages, and it is a step forward to identify virulence markers and their mechanisms of spread. Surveillance should focus not only on antimicrobial resistance but also on virulence characteristics to avoid the spread of multidrug (hyper)virulent K. pneumoniae that may cause untreatable and more severe infections.