| Abstract [eng] |
The growing resistance to the antimicrobial treatment and the increasing number of bacterial and fungal skin diseases are the key problems promoting the research of the new antifungal and antibacterial compounds. Silver nanoparticles have excellent antimicrobial properties against various pathogenic microorganisms. The properties of silver nanoparticles depend from their size, composition, surface modifications, and the properties of microorganism to which they are exposed. In addition, silver nanoparticles have a complex effect against microorganisms, damaging their cell walls and membranes, disrupting their protein and DNA synthesis, and promoting the production of ROS. This thesis describes the antimicrobial effects of silver nanoparticles synthesized by bacteria of genus Geobacillus against skin pathogens: Candida lusitaniae and C. guilliermondii yeasts, the pseudohyphae of C. lusitaniae, and Staphylococcus aureus, Streptococcus pyogenes and Pseudomonas aeruginosa bacteria. In the case of yeasts, the most effective were Geobacillus sp. 25 strain silver nanoparticles, whereas in the case of bacteria, Geobacillus sp. 95 strain silver particles were the most effective. In addition, the MIC values of Geobacillus sp. silver nanoparticles for the mentioned microorganisms were evaluated. This thesis also analyzes the dynamics of the effect of silver nanoparticles on pathogens to find out at what point in time their antimicrobial activity begins. It was determined that the antimicrobial effect of all Geobacillus sp. Silver nanoparticles begins within first four hours of growth (except for the pseudohyphae of C. lusitaniae). The synergistic effect of silver nanoparticles obtained by Geobacillus sp. bacteria induced synthesis and electroporation on yeast cells of the genus Candida was also established. |
