20.500.12556/RUL-177353 Sposobnost tvorbe biofilma izbranih sevov bakterije Escherichia coli Biofilm formation of selected Escherichia coli strains V raziskavi smo primerjali 58 izolatov bakterije Escherichia coli, ki smo jih pridobili iz različnih okoljskih virov (N=26) v Sloveniji (morska voda, rečna voda, kraške jame, tesnila pomivalnih strojev) ter iz kliničnih vzorcev spodnjih dihal (N=32). Izolate smo uvrstili v filogenetske skupine po izvirni in prenovljeni Clermontovi metodi ter preverili njihovo klonalnost z metodo ERIC-PCR. Z uporabo molekularnih metod smo preverili prisotnost 20 genov za dejavnike virulence, genov z zapisi za β-laktamaze, gene z zapisi za plazmidno posredovano odpornost proti fluorokinolonom ter izbrane sekvenčne tipe. Sposobnost tvorbe biofilma smo ovrednotili pri različnih razmerah (čas in prisotnost UV), pri čemer je bila končna koncentracija glukoze v gojišču omejujoč dejavnik. Rezultati analize so pokazali izrazite razlike med obema skupinama. Klinični izolati so se večinoma uvrščali v filogenetske skupine, ki so značilne za bolj virulentne in patogene izolate (B2; 68,75 %), in so imeli večje število genov za dejavnike virulence. Sposobnost tvorbe biofilma je med izolati in načinom gojenja biofilma močno variirala. V hranilno bogatem gojišču LB so bile razlike v tvorbi biofilma med izolati manjše, medtem ko je v minimalnem gojišču z 0,2 % glukoze nastalo več biofilma, neodvisno od izvora izolatov. Klinični izolati so bili močno biofilmotvorni, še posebej v minimalnem gojišču z 0,2 % končne koncentracije glukoze (96,9 %). We compared 58 Escherichia coli isolates obtained from various environmental sources in Slovenia (N = 26; seawater, river water, karst cave waters, and dishwasher rubber seals) and from clinical lower respiratory tract samples (N = 32). The isolates were assigned to phylogenetic groups using both the original and the revised Clermont methods, and their clonality was assessed using ERIC-PCR. Using molecular methods, we examined the presence of 20 virulence genes, genes encoding β-lactamases, genes associated with plasmid-mediated resistance to fluoroquinolones, and selected sequence types. Biofilm-forming ability was assessed under various conditions by altering nutrient availability, concentrations of trace elements, and the presence of subinhibitory concentrations of antimicrobial compounds.The results revealed pronounced differences between the two groups. Clinical isolates predominantly belonged to phylogenetic groups characteristic of more virulent and pathogenic strains (B2; 68.75%) and more frequently carried a greater number of virulence-associated genes. Biofilm formation varied significantly among the isolates and depended on the biofilm cultivation method. In the nutrient-rich LB medium, differences in biofilm formation between isolates were smaller, whereas in the minimal medium with 0.2 % glucose, more biofilm was produced regardless of the isolates’ origin. Clinical isolates were strong biofilm producers, especially in the minimal medium with 0.2 % final glucose concentration (96.9 %), while environmental isolates showed greater diversity. Escherichia coli geni za dejavnike virulence filogenetske skupine odpornost proti protimikrobnim učinkovinam tvorba biofilma Escherichia coli virulence factor genes phylogenetic groups antimicrobial resistance biofilm formation true false false [Š. Lepičnik] Slovenski jezik Angleški jezik Magistrsko delo/naloga 2025-12-21 07:16:55 2025-12-21 07:17:01 2026-01-06 11:13:24 0000-00-00 00:00:00 2025 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 1970-01-01 579.84(043.2) 277616 263545091 55629.pdf 55629.pdf 1 68793643E26C4BFECD5116F1503C2F14 0852fe514de4495d334d101fc96c81e1fd0f2542e98965e32d5d8c00f772f752 3cd755b7-de34-11f0-9328-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=224317 Biotehniška fakulteta 0 0 0