Three Klebsiella pneumoniae lineages causing bloodstream infections variably dominated within a Greek hospital over a 15 year period

Carbapenem-resistant Klebsiella pneumoniae (CRKP) has emerged as a major clinical and public health threat. The rapid dissemination of this pathogen is driven by several successful clones worldwide. We aimed to investigate the CRKP clonal lineages, their antibiotic resistance determinants and their potential transmissions in a tertiary care hospital located in Athens, Greece. Between 2003 and 2018, 392 CRKP isolates from bloodstream infections were recovered from hospitalized patients. Whole genome sequencing (WGS) was performed on the Illumina platform to characterize 209 of these isolates. In total, 74 % (n=155) of 209 isolates belonged to three major clonal lineages: ST258 (n=108), ST147 (n=29) and ST11 (n=18). Acquired carbapenemase genes were the mechanisms of resistance in 205 isolates (bla (KPC), n=123; bla (VIM), n=56; bla (NDM), n=20; bla (OXA-48), n=6). Strong associations (P=0.0004) were observed between carbapenemase genes and clonal lineages. We first isolated bla (VIM-1)-carrying ST147 strains during the early sampling period in 2003, followed by the emergence of bla (KPC-2)-carrying ST258 in 2006 and bla (NDM-1)-carrying ST11 in 2013. Analysis of genetic distances between the isolates revealed six potential transmission events. When contextualizing the current collection with published data, ST147 reflected the global diversity, ST258 clustered with isolates representing the first introduction into Europe and ST11 formed a distinct geographically restricted lineage indicative of local spread. This study demonstrates the changing profile of bloodstream CRKP in a tertiary care hospital over a 15 year period and underlines the need for continued genomic surveys to develop strategies to contain further dissemination. This article contains data hosted by Microreact.