Introduction

Klebsiella pneumoniae (Kp), an opportunistic bacterium in animals and humans and common cause of nosocomial infections, has evolved to a novel pathotype known as hypervirulent (hv) Kp. HvKp strains are associated with severe infections in otherwise healthy individuals. Virulence and resistance traits are usually located on different plasmids. Recently, convergence plasmids carrying both antibiotic resistance and virulence-associated genes have been reported in various countries worldwide.

Goals

The presence of resistance- and virulence-associated genes in Kp isolates from German patients, along with convergence plasmids is poorly investigated, necessitating comprehensive plasmid analyses.

Methods

Genomes of 62 Kp isolates with PCR confirmed presence of virulence associated genes were analysed using short and long-read sequencing. We applied bioinformatics tools (Kleborate, MOBsuite, AMRfinder) to identify multi-locus sequence types, capsule types, plasmid types, resistance and virulence genes. Whole genome alignment aided phylogenetic studies of similar plasmid types available in public databases and described as virulence, resistance or convergence plasmids.

Results

MOBsuite analyses revealed that 18/62 isolates harbored >6 different plasmids. Three major types of plasmids carrying only resistance genes were found in 38 isolates; the typical hv associated plasmid was found in 15 isolates (mainly sequence type ST23). Resistance and virulence genes were present on different plasmids in 9 isolates but in 28 isolates (mainly ST147 and ST395) convergence plasmids were identified. These plasmids carried both carbapenemase genes (blaNDM) and virulence associated genes (rmpA/A2, iuc).

Summary

This study showed the presence of typical hvKp strains of ST23 with or without additional resistance plasmids in Germany. A remarkable number of isolates of known global epidemic lineages (ST147, ST395) carried convergence plasmids contributing to the pathogenic potential and antibiotic resistance burden of these strains. Our findings shed light on the intricate interplay between resistance and virulence traits that has to be investigated in future studies.