Vrednotenje bakterijske odpornosti in sposobnosti tvorbe biofilma bakterij rodu Enterococcus

Gorenjšček, Zala (avtor), Hrast Rambaher, Martina (mentor), Golob, Majda (komentor)

Bakterijska odpornost proti antibiotikom predstavlja enega največjih izzivov sodobne medicine, pri čemer so enterokoki, zlasti vrsti Enterococcus faecium in Enterococcus faecalis, med pomembnejšimi povzročitelji bolnišničnih okužb. Zaradi njihove sposobnosti pridobivanja genov odpornosti in tvorbe biofilmov je zdravljenje teh okužb vse zahtevnejše, zato Svetovna zdravstvena organizacija uvršča vrsto E. faecium med bakterije z visoko prioriteto za razvoj novih protibakterijskih učinkovin. Namen magistrskega dela je bil ovrednotiti protibakterijsko delovanje izbranih spojin iz knjižnice Fakultete za farmacijo proti večkratno odpornemu sevu E. faecium (EFM 30088/16) in referenčnemu sevu E. faecalis (RDK057) ter hkrati preučiti njuno sposobnost tvorbe biofilma. Določitev minimalne inhibitorne koncentracije (MIK) je bila izvedena z mikrodilucijsko metodo, občutljivost za antibiotike je bila ocenjena s ploščo Sensititre™ EUVENC v skladu s smernicami EUCAST. Izmed 840 testiranih spojin smo za 25 potrdili protibakterijsko delovanje (MIK < 128 μg/mL). Najobetavnejši so bili N-tiosubstituirani β-laktami (GDL-59, GDL-64, GDL-66, GDL-88 in GDL-89), pri katerih so bile izmerjene vrednosti MIK med 8 in 16 μg/mL, kar nakazuje močan zaviralni učinek, predvsem pri vrsti E. faecalis. Izbrane spojine iz razreda MurF-inhibitorjev (10A12 in 10B12) ter novi kemijski entiteti 4B10 in 4F1 so izkazale zmerno protimikrobno aktivnost. Analiza fizikalno-kemijskih lastnosti je pokazala, da večina aktivnih spojin ustreza Lipinskemu pravilu, pri čemer izstopa GDL-66 kot spojina z ugodnim farmakokinetičnim profilom. Pri oceni tvorbe biofilma se je E. faecalis izkazal kot šibko filmotvoren, medtem ko E. faecium v danih pogojih biofilma ni tvoril. Rezultati kažejo, da imajo izbrane spojine, zlasti tiste iz razreda GDL, potencial za nadaljnji razvoj novih učinkovin proti večkratno odpornim enterokokom in prispevajo k boljšemu razumevanju povezave med odpornostjo ter filmotvornostjo teh bakterij.

• Jezik: Slovenski jezik
• Ključne besede: Enterococcus faecium, Enterococcus faecalis, bakterijska odpornost, protibakterijsko delovanje, knjižnica spojin, minimalna inhibitorna koncentracija, biofilm
• Vrsta gradiva: Magistrsko delo/naloga
• Tipologija: 2.09 - Magistrsko delo
• Organizacija: FFA - Fakulteta za farmacijo
• Leto izida: 2025
• PID: 20.500.12556/RUL-176640
• COBISS.SI-ID: 260428291
• Datum objave v RUL: 06.12.2025

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: Evaluation of bacterial resistance and biofilm formation in Enterococcus species

Izvleček

Bacterial resistance to antibiotics represents one of the major challenges in modern medicine, with enterococci, particularly Enterococcus faecium and Enterococcus faecalis, being among the most important causative agents of hospital-acquired infections. Their ability to acquire resistance genes and form biofilms makes these infections increasingly difficult to treat. Consequently, the World Health Organization has classified E. faecium among the high-priority pathogens for the development of new antibacterial agents. The aim of this master’s thesis was to evaluate the antibacterial activity of selected compounds from the Faculty of Pharmacy compound library against a multidrug-resistant strain of E. faecium (EFM 30088/16) and a reference strain of E. faecalis (RDK057), as well as to investigate their biofilm-forming ability. The minimum inhibitory concentration (MIC) was determined using the broth microdilution method, while antibiotic susceptibility was assesed using the Sensititre™ EUVENC panel according to EUCAST guidelines. Among the 870 tested compounds, 25 showed confirmed antibacterial activity (MIC < 128 μg/mL). The most promising were the N-thiosubstituted β-lactams (GDL-59, GDL-64, GDL-66, GDL-88, and GDL-89), with MIC values ranging from 8 to 16 μg/mL, indicating a strong inhibitory effect, particularly against E. faecalis. Some compounds from the class of MurF inhibitors (e.g., 10A12 and 10B12) and two novel chemical entities (4B10 and 4F1) also exhibited moderate activity. Physicochemical analysis showed that most of the active compounds comply with Lipinski’s rule, with GDL-66 standing out due to its favorable pharmacokinetic profile. In the biofilm formation assessment, E. faecalis exhibited weak biofilm-forming ability, whereas E. faecium did not form biofilm under the tested conditions. The results indicate that the selected compounds, particularly those from the GDL class, have potential for further development as novel agents against multidrug-resistant enterococci and contribute to a better understanding of the relationship between resistance and biofilm formation in these bacteria.

• Ključne besede: Enterococcus faecium, Enterococcus faecalis, bacterial resistance, antibacterial activity, compound library, minimum inhibitory concentration, biofilm