Virulomic Analysis of Multidrug-Resistant Klebsiella pneumoniae Isolates and Experimental Virulence Model Using Danio rerio (Zebrafish)

This study evaluates a possible correlation between multidrug-resistant Klebsiella pneumoniae strains and virulence markers in a Danio rerio (zebrafish) model. Whole-genome sequencing (WGS) was performed on 46 strains from three Brazilian hospitals. All of the isolates were colistin-resistant and harbored bla(KPC-2). Ten different sequence types (STs) were found; 63% belonged to CC258, 22% to ST340, and 11% to ST16. The virulence factors most frequently found were type 3 fimbriae, siderophores, capsule regulators, and RND efflux-pumps. Six strains were selected for a time-kill experiment in zebrafish embryos: infection by ST16 was associated with a significantly higher mortality rate when compared to non-ST16 strains (52% vs. 29%, p = 0.002). Among the STs, the distribution of virulence factors did not differ significantly except for ST23, which harbored a greater variety of factors than other STs but was not related to a higher mortality rate in zebrafish. Although several virulence factors are described in K. pneumoniae, our study found ST16 to be the only significant predictor of a virulent phenotype in an animal model. Further research is needed to fully understand the correlation between virulence and sequence types.

Automated summary

This study found that in a zebrafish model, ST16 was significantly associated with a more virulent phenotype in Klebsiella pneumoniae strains. Although there are multiple virulence factors in K. pneumoniae, ST16 was identified as the only significant predictor of virulence in an animal model. Further research is needed to fully understand the correlation between virulence and sequence types.