Genetic factors in the accessory genome of Pseudomonas aeruginosa and Klebsiella pneumoniae associated with pathogenicity

Abstract

Pseudomonas aeruginosa and Klebsiella pneumoniae are among the main microorganisms responsible for health care-associated infections. The population structure of these pathogens includes multiresistant clones often related to outbreaks in different geographic regions, the so-called high-risk clones. The pan-genome of P. aeruginosa and K. pneumoniae is constantly expanding, with an accessory genome harboring a diversity of pathogenicity islands, resistance and virulence markers, and plasmids, that contribute to the occurrence of hypervirulent and multiresistant isolates. In this study, we will investigate the accessory genome of high-risk clones of P. aeruginosa and K. pneumoniae to identify features possibly related to virulence and persistence of these clones in the clinical environment, as well as features facilitating the transition from colonization to infection. Hypotheses generated in silico using public databases and results from our research group will be investigated in an experimental model of infection using Caenorhabditis elegans. Additionally, the genetic background of microorganisms may contribute to metabolic gene expression alterations that affect their performance during colonization and infection. Thus, we will also investigate the expression levels of a set of genes from the core genome, in vitro and in vivo using C. elegans as the experimental model for infection, in order to understand their contribution to virulence or to the transition from colonization to infection. This study aims to contribute to a better understanding of mechanisms associated with the pathogenicity of two microorganisms of great relevance in clinical setting.