Analysis of the hypovirulent Klebsiella pneumoniae with the NDM-5 gene on IncN plasmids

Abstract

ABSTRACT Our study aims to analyze the hypovirulent Klebsiella pneumoniae with the NDM-5 gene on IncN plasmids. This strain was isolated from a patient with a liver abscess, and the ST type was ST147. The characterization, antimicrobial drug resistance, and virulence of the strain with the NDM-5 gene on IncN plasmids were analyzed by whole-genome sequencing. Virulence testing was conducted using the Galleria mellonella infection model, serum killing, and biofilm formation assay. Growth measurement analysis, an in vitro competition experiment, and a plasmid stability assay were calculated using fitness costs. A conjugation assay was used to test NDM-5 transfer between bacterial strains. For statistical analysis and image visualization, GraphPad Prism 8.0 was employed. The result revealed that the hypovirulent strain with the NDM-5 gene was located on the IncN plasmid (92.284 kb), which is rare in Klebsiella pneumoniae . Whole-genome sequencing revealed the presence of 25 and 22 resistance and virulence genes, respectively. The strain KP4089 was resistant to carbapenems, β-lactam, ceftazidime-avibactam, and macrolides but remained susceptible to aminoglycosides, mucilage, and tigecycline in antimicrobial susceptibility tests. Furthermore, the strain KP4089 exhibited significantly lower serum killing and biofilm formation rates, demonstrating that the strain with the NDM-5 gene had low virulence. The strain with the NDM-5 gene on the IncN plasmid was genetically stable and had no fitness cost associated with identifying IncN plasmids. Future research should focus on clinical surveillance of hypovirulent multidrug-resistant Klebsiella pneumoniae to identify the potential strain and mechanistic studies to prevent its spread. IMPORTANCE It is crucial to strengthen the ongoing clinical surveillance of non-highly virulent, multi-resistant Klebsiella pneumoniae .