| Abstract [eng] |
Nosocomial infections caused by multidrug resistant opportunistic bacteria are spread worldwide. Among these infection agents, the highest resistance is observed among Acinetobacter baumannii strains. This doctoral thesis is aimed to characterise A. baumannii strains, isolated in Lithuanian hospitals, for the various phenotypes related to virulence. Studies have shown that strains belonging to the predominant pandemic clones differ in their motility, pellicle formation and profiles of capsular exopolysaccharides. It has been shown that the hydrophobicity of the bacterial surface determines numerous A. baumannii properties related to virulence, and the ability to adhere to the plastic due to the cell surface hydrophobicity was a predominant feature of the pandemic strains. In the second part of the thesis, A. baumannii surface proteins OmpA, Blp1, YgaU and GltI were characterised as important virulence factors ex vivo and in vivo. It has been demonstrated that the loss of interaction between membrane protein OmpA and peptidoglycan results in a decrease of multifunctional virulence potential of A. baumannii. Finally, the C-terminal fragment of the Blp1 protein was described as a new vaccine candidate against clinical A. baumannii infections using both active and passive vaccinations in the mouse infection model. |
