Functional characterization of a putative motility modulator in Klebsiella pneumoniae and its role in the pathogenicity of this bacterium.

Abstract

Klebsiella pneumoniae is a Gram-negative bacterium responsible for a wide-range of healthcare-associated infections, particularly in immunocompromised patients. In recent years, the world has been facing the emergence of hypervirulent and multidrug-resistant K. pneumoniae isolates. Moreover, the increasing number of severe community-acquired infections even in healthy individuals has emphasized the importance of characterizing the virulence factors that determine the pathogenicity of K. pneumoniae. In many bacteria, flagella-mediated motility is an important virulence factor. Regarding K. pneumoniae, there is a consensus in the literature that this is a bacterium that does not encode flagella. Nonetheless, recent studies have provided evidence that K. pneumoniae encodes flagellum-like and/or pili structures that have the potential to promote motility in this bacterium. In addition, this bacterium has, in its annotated genome, a gene called flk that encodes a putative regulator of flagellar biosynthesis. However, the role of this gene in K. pneumoniae is still unknown. In this sense, the present study aims to investigate the role of flk in K. pneumoniae, through the characterization of a strain mutant to the flk gene. Phenotypic assays - such as biofilm formation, motility, and gene expression analyses - will be performed with the wild-type and the mutant strains to determine the role of flk in the pathogenicity of K. pneumoniae. The results to be obtained from the present research will help elucidate whether the flk gene plays a role in the motility, even if it is rudimentary, in K. pneumoniae, and will contribute to a better understanding of the pathogenicity of this bacterium. (AU)