20.500.12556/RUL-176281 Protibakterijsko vrednotenje novih zaviralcev metalobetalaktamaz Antibacterial evaluation of new inhibitors of metallobetalactamases Antibiotiki predstavljajo eno najpomembnejših odkritij v sodobni medicini, saj omogočajo učinkovito zdravljenje bakterijskih okužb ter so pomembno prispevali k podaljšanju življenjske dobe in zmanjšanju smrtnosti zaradi infekcij. Gre za protibakterijske učinkovine naravnega ali sinteznega izvora, ki uničujejo bakterije ali zavirajo njihovo rast. Razlikujejo se glede na mehanizem delovanja, spekter učinkovitosti ter kemično zgradbo, pri čemer ločimo več glavnih skupin, kot so aminoglikozidi, makrolidi, tetraciklini, kinoloni, glikopeptidi, sulfonamidi in βlaktamski antibiotiki. V zadnjih desetletjih pa vse bolj narašča problematika pojavnosti odpornosti bakterij proti antibiotikom, kar predstavlja eno največjih groženj javnemu zdravju. Bakterije lahko razvijejo odpornost prek različnih mehanizmov, kot so razgradnja antibiotikov z encimi, sprememba tarčnih mest, zmanjšana prepustnost membrane in aktivno izčrpavanje učinkovin. Posebno skrb vzbujajo β-laktamaze, encimi, ki razgrajujejo β-laktamske antibiotike z razcepom njihovega značilnega obroča. Med β-laktamaze sodijo tudi metalo-β-laktamaze, ki za svojo katalitično dejavnost potrebujejo dvovalentne kovinske ione, najpogosteje cink. Za zaviranje delovanja β-laktamaz se uporabljajo zaviralci, kot so klavulanska kislina, sulbaktam in avibaktam, vendar so ti učinkoviti le proti serinskim β-laktamazam. Velik izziv tako ostaja pomanjkanje učinkovitih zaviralcev metalo-β-laktamaz, saj njihova strukturna raznolikost otežuje razvoj selektivnih in netoksičnih učinkovin. V sklopu magistrske naloge smo preverili, ali katera izmed izbranih spojin iz knjižnice spojin Fakultete za farmacijo Univerze v Ljubljani izkazuje sinergistično protimikrobno delovanje v kombinaciji z antibiotikom meropenemom. Testiranja smo izvedli na sevih bakterij iz družine enterobakterij, Escherichia coli in Salmonella z izraženimi metalo-β-laktamazami. Najprej smo določili protibakterijsko delovanje posameznih spojin in njihove minimalne inhibitorne koncentracije. Skladno s smernicami EUCAST za leto 2025 je klinična mejna vrednost občutljivosti za meropenem pri enterobakterijah ≤ 2 µg/mL, medtem ko vrednosti nad 8 µg/mL označujejo odpornost bakterij proti meropenemu. Med 88 testiranimi kombinacijami smo pri spojinah MBL-3, MBL-14, MBL-17, MBL-35 in MBL-39 in določili šibko sinergistično delovanje v kombinaciji z meropenemom. Antibiotics represent one of the most important discoveries in modern medicine, as they enable effective treatment of bacterial infections and have significantly contributed to increased life expectancy and reduced mortality due to infectious diseases. They are antibacterial agents of natural or synthetic origin that either kill bacteria or inhibit their growth. Antibiotics differ in their mechanism of action, spectrum of activity, and chemical structure, with the main groups including aminoglycosides, macrolides, tetracyclines, quinolones, glycopeptides, sulfonamides, and β-lactam antibiotics. In recent decades, the emergence of antimicrobial resistance has become an increasing public health threat. Bacteria can develop antimicrobial resistance through various mechanisms including enzymatic degradation of antibiotics, alteration of target sites, reduced membrane permeability, and active efflux of antimicrobial agents. Of particular concern are β-lactamases, enzymes that hydrolyze β-lactam antibiotics by breaking their characteristic β-lactam ring. Among β-lactamases, metallo-β-lactamases, constitute a distinct subclass characterized by dependence on divalent metal ions, most commonly zinc, to mediate hydrolytic cleavage of the β-lactam ring. To inhibit β-lactamase activity, inhibitors such as clavulanic acid, sulbactam, and avibactam are used; however, these are only effective against serine βlactamases. A major challenge remains the lack of effective inhibitors against MBLs, as their structural diversity complicates the development of selective and non-toxic compounds. In this master’s thesis, we investigated whether any of the selected compounds from the compound library of the Faculty of Pharmacy, University of Ljubljana, exhibit synergistic antimicrobial activity in combination with the antibiotic meropenem. Testing was performed on bacterial strains from the Enterobacteriaceae family, namely Escherichia coli and Salmonella, expressing metallo-β-lactamases. First, the antibacterial activity of individual compounds was assessed, and their minimum inhibitory concentration were determinated. According to EUCAST guidelines for 2025, the clinical susceptibility breakpoint for meropenem in Enterobacteriaceae is ≤ 2 µg/mL, while values above 8 µg/mL indicate resistance. Among the 88 tested combinations, weak synergistic activity with meropenem was observed for compounds MBL-3, MBL-14, MBL-17, MBL-35, and MBL-39. metalo-β-laktamaze β-laktamski antibiotiki odpornost bakterij proti protimikrobnim zdravilom inhibitorji β-laktamaz minimalna inhibitorna koncentracija metallo-β-lactamases β-lactam antibiotics antimicrobial resistance β-lactamase inhibitors minimum inhibitory concentration true false false Slovenski jezik Angleški jezik Magistrsko delo/naloga 2025-11-26 12:33:26 2025-11-26 12:33:34 2025-12-19 04:09:16 0000-00-00 00:00:00 2025 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 122108 259005955 31431.pdf 31431.pdf 1 FB71859A8BB590094A43ECB207D390C8 91921c00040e97bb8a1db302cced38ee2208d43daf8131fc3e18feabecc838d4 609f38eb-cabb-11f0-9328-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=222565 Fakulteta za farmacijo 0 0 0