20.500.12556/RUL-191295 Sinteza in mikrobiološko vrednotenje konjugatov monobaktamov s trifenilfosfinom Synthesis and microbiological assessment of triphenylphosphine- monobactam conjugates Beta-laktamski antibiotiki sodijo med najpomembnejše skupine protibakterijskih učinkovin, vendar njihovo učinkovitost vse bolj omejuje razvoj bakterijske rezistence ter sposobnost bakterij za tvorbo biofilmov. Biofilm je organizirana mikrobna skupnost, obdana z zunajceličnim polimernim matriksom, ki bakterijam omogoča večjo odpornost proti antibiotikom in obrambnim mehanizmom gostitelja. Zaradi naraščajoče razširjenosti večkratno odpornih gramnegativnih bakterij je potreba po razvoju novih protibakterijskih učinkovin z izboljšano aktivnostjo in sposobnostjo zaviranja biofilmov vse večja. Namen magistrskega dela je bil sintetizirati nove monobaktamske derivate s trifenilfosfinskimi substituenti ter vrednotenje njihove protibakterijske aktivnosti in sposobnosti zaviranja nastanka bakterijskih biofilmov. Izhajali smo iz znanih lastnosti aztreonama, ki ima dobro aktivnost proti gramnegativnim bakterijam, vendar omejen vpliv na biofilm. Predvidevali smo, da bi uvedba različnih trifenilfosfinskih distančnikov lahko izboljšala interakcije spojin z bakterijsko membrano in vplivala na razvoj biofilmov. V eksperimentalnem delu smo sintetizirali več novih monobaktamskih konjugatov z različnimi trifenilfosfinskimi distančniki, ki smo jih na aztreonamsko ogrodje pripeli bodisi z zaestrenjem sulfonske skupine, bodisi z uvedbo amidne vezi na karboksilni skupini. Sintetizirane spojine smo ovrednotili z jedrsko magnetno resonanco, masno spektrometrijo in tekočinsko kromatografijo ultra visoke ločljivosti. Protibakterijsko delovanje smo ovrednotili v sodelovanju z zaposlenimi na Veterinarski fakulteti UL z določanjem minimalnih inhibitornih koncentracij na različnih bakterijskih sevih, med drugim Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii in Staphylococcus aureus. Poleg tega smo z metodo barvanja biofilmov s kristalvijoličnim preučevali vpliv spojin na nastanek bakterijskih biofilmov na sevu Pseudomonas aeruginosa (PAO1). Rezultati vrednotenja protibakterijske aktivnosti so bili različni pri različnih bakterijskih sevih. Aktivnost je bila odvisna od strukture spojin, zlasti od dolžine distančnika. Pri testiranju na biofilme so nekatere spojine, zlasti spojini 20 in 18, pomembno zmanjšale delež nastalega biofilma. Določene spojine so učinkoviteje zavirale rast planktonskih bakterij (spojina 14 S. aureus, spojini 8 in 9 K. pneumoniae, spojina 9 P. aeruginosa, spojini 18 in 20 E. coli) , druge pa so izraziteje vplivale na nastanek biofilma. Rezultati nakazujejo, da predstavljajo sintetizirani trifenilfosfinski monobaktamski konjugati obetavno izhodišče za nadaljnji razvoj novih učinkovin proti gramnegativnim bakterijam, ki tvorijo biofilme. Beta-lactam antibiotics represent one of the most important classes of antibacterial agents; however, their efficacy is increasingly compromised by the emergence of bacterial resistance and the ability of bacteria to form biofilms. A biofilm is an organized microbial community embedded within an extracellular polymeric matrix, which provides bacteria with enhanced protection against antibiotics and host defense mechanisms. Due to the increasing prevalence of multidrug-resistant Gram-negative bacteria, there is a growing need for the development of novel antibacterial agents with improved activity and the ability to inhibit biofilm formation. The aim of this master’s thesis was to synthesize novel monobactam derivatives containing triphenylphosphine substituents and to evaluate their antibacterial activity and antibiofilm potential. The study was based on the known properties of aztreonam, which exhibits good activity against Gram-negative bacteria but has limited effects on biofilms. We hypothesized that the introduction of different triphenylphosphine linkers could enhance the interactions of the compounds with the bacterial membrane and consequently influence biofilm development. In the experimental part, several novel monobactam conjugates with different triphenylphosphine linkers were synthesized. The triphenylphosphine moieties were attached to the aztreonam scaffold either through esterification of the sulfonic acid group or via formation of an amide bond at the carboxyl group. The synthesized compounds were characterized by nuclear magnetic resonance spectroscopy, mass spectrometry, and ultra-highperformance liquid chromatography. Antibacterial activity was evaluated by determining the minimum inhibitory concentrations against various bacterial strains, including Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii, and Staphylococcus aureus. In addition, the influence of the compounds on bacterial biofilm formation in the Pseudomonas aeruginosa (PAO1) strain was investigated using the crystal violet assay. The results of antibacterial evaluation differed among the tested bacterial strains. The activity depended on the structural properties of the compounds, particularly on the linker length. In the biofilm assays, some compounds, especially compound number 20 and 18, significantly reduced the extent of biofilm formation. Certain compounds more effectively inhibited the growth of planktonic bacteria (compound 14 S. aureus, compounds 8 and 9 K. pneumoniae, compound 9 P. aeruginosa, compounds 18 and 20 E. coli), whereas others showed a more pronounced effect on biofilm formation. The obtained results indicate that the synthesized triphenylphosphine monobactam conjugates represent promising lead compounds for the further development of novel agents targeting biofilm-forming Gram-negative bacteria. Monobaktamski antibiotiki gramnegativne bakterije trifenilfosfin bakterijski biofilmi Monobactam antibiotics Gram-negative bacteria triphenylphosphine bacterial biofilms true false false Slovenski jezik Angleški jezik Magistrsko delo/naloga 2026-11-14 08:45:09 2026-11-14 08:45:23 2026-11-15 04:29:42 0000-00-00 00:00:00 2026 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 1970-01-01 138544 38364.pdf 38364.pdf 1 99D1A980D5D10B13D883F847DD2B5BB7 b9ee4692519203177c5150e29cc58e32997e657a9737514830180ca06dbd8db5 3c27c6e2-dfff-11f1-aea2-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=253362 Fakulteta za farmacijo 0 0 0