Determination of Adhesion and Colonisation Intensity of Staphylococcus epidermidis and Pseudomonas aeruginosa on the Surface of Originally Synthesised Biomaterials in vitro and in vivo Studies, and Their Impact on Inflammatory Cytokine Expression in Tissues. Summary of the Doctoral Thesis

Abstract

Aim of this work was to investigate in vitro the adhesion and colonization intensity of the Staphylococcus epidermidis and Pseudomonas aeruginosa on surfaces of biomaterials originally synthesized in Latvia, as well as to assess bacterial colonization intensity in vivo, and to study its effects on expression of inflammatory cytokines (IL-10, TNF-α) and antimicrobial peptides (beta-defensin-2) in tissues. The normal microflora representatives have the ability to colonize the implanted objects which can cause implant-related infections; therefore during the research it was necessary to clarify biomaterials according to their chemical composition, manufacturing, and with ability to resist bacteria. Considering these features the most prospective biomaterials were chosen. In this study we used 32 originally synthesized biomaterials with different chemical compositions and different types of manufacturing. In vitro research showed that bacterial adhesion and colonization of HAp/TiO2 and HAp/Ag containing biomaterials was much less intense. Therefore these biomaterials were recommended for further development and practical application. The in vivo study discovered that ceramic biomaterials were colonized more intensely by P. aeruginosa than by S. epidermidis. Studies also showed that Pseudomonas tend to cause the depletion of β-defensin-2 production in the tissue, while after 3 months of exposure the expression of all cytokines was decreased in tissue samples only.