BACTERIAL FACTORS THAT MODULATE COLONIZATION AND PATHOGENESIS OF HYPERVIRULENT KLEBSIELLA PNEUMONIAE IN THE GASTROINTESTINAL TRACT

Abstract

Hypervirulent Klebsiella pneumoniae (HvKp) is the primary cause of monomicrobial liver abscess in Asia. HvKp colonises the gastrointestinal tract prior to systemic infection. In this work, we studied pathogenic determinants associated with clonal group 23-I, the dominant lineage of HvKp. We determined that bacterial capsule is dispensable during gastrointestinal colonisation although it is crucial for protection against the innate immune response. Moreover, we developed a murine model of gastrointestinal translocation by HvKp. We also investigated genomic islands GIE492 and ICEKp10, responsible for the production of bacteriocin mccE492 and genotoxin colibactin respectively. HvKp utilises mccE492 and colibactin cooperatively to kill bacterial species in the gut, causing changes to the gut microbiome that benefits colonisation. Thus, besides the importance of capsule in systemic infection, the presence of mccE492 and colibactin in HvKp could contribute to a competitive advantage in the gut and the success and dominance of the CG23-I-lineage.