20.500.12556/RUL-183372 Določanje hemolizina BL in genov za enterotoksine pri skupini Bacillus cereus iz živil, brisov površin in človeških iztrebkov Determination of hemolysin BL and genes of enterotoxins in Bacillus cereus group from food, surface swabs and human feaces Skupina Bacillus cereus sensu lato je pomemben povzročitelj zastrupitev s hrano in zaradi svoje razširjenosti v živilih, okolju in človeški mikrobioti predstavlja vse večji izziv za mikrobiološko diagnostiko. Ključni dejavniki virulence zajemajo diarealne enterotoksine Hbl, Nhe in CytK, vendar je molekularna opredelitev teh genov v slovenskih izolatih še vedno slabo raziskana. Namen naše raziskave je bil razviti in optimizirati metodo PCR v realnem času za hkratno detekcijo genov hblD, nheA in cytK2, ter z njo oceniti razširjenost enterotoksinskih zapisov v izolatih skupine B. cereus s. l. iz živil, brisov površin in človeških iztrebkov. Metoda je bila optimizirana in validirana postopno. V raziskovalno nalogo smo vključili 179 izolatov, med katerimi je bil gen nheA najpogostejši (98 %), kombinacija vseh treh diarealnih genov je bila prisotna pri približno polovici izolatov. Primerjava rezultatov PCR in BCET RPLA je pokazala visoko stopnjo skladnosti med metodama (98 %). Ugotovitve potrjujejo, da razvita metoda zanesljivo omogoča genotipsko opredelitev enterotoksinskega profila in nakazuje na veliko razširjenost toksinskih genov skupine B. cereus s. l. v preučevanih okoljih. The Bacillus cereus sensu lato group represents a significant food safety concern, as its widespread presence in food, the environment and in the human gut contributes to frequent diarrheal and emetic foodborne illnesses. Despite the importance of its major virulence determinants, enterotoxins Hbl, Nhe, CytK, molecular characterization of toxin genes in Slovenian isolates remains limited. The aim of this study was to develop and optimize a realtime PCR method for the simultaneous detection of hblD, nheA and cytK2, and to assess the prevalence of these genes in isolates obtained from food, surface swabs and human feces samples. The method was optimized and validated stepwise. We examined 179 isolates in the study, among which the nheA gene was the most common gene (98 %), while the combination of all three diarrheal genes occured in approximately half of the isolates. A comparison of PCR with BCET RPLA results demonstrated high concordance (98 %). Overall, our findings show that the developed method provides a reliable genotypic tool for characterization of the enterotoxin profiles of strains from B. cereus s. l. group and reveal a broad distribution of toxin genes of this bacterial group across the studied environments. bakterije skupina Bacillus cereus sensu lato enterotoksini hemolizin BL vzorci živila brisi površin človeški iztrebki molekularne metode PCR bacteria Bacillus cereus sensu lato group enterotoxins hemolysin BL samples food surface swabs human feces molecular methods PCR true false false [J. Lebar] Slovenski jezik Angleški jezik Magistrsko delo/naloga 2026-06-12 07:15:19 2026-06-12 07:15:52 2026-06-13 04:29:38 0000-00-00 00:00:00 2026 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 579.25:579.852.11:615.9 280075 281386243 57613.pdf 57613.pdf 1 F2A0090741E79B4DA6B81638D6A5A72A ed61acf4ea517396fb24eea634d2daaa0d2fb2ccfa8415e487adffd563e09b61 d162306f-661d-11f1-9b0d-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=235396 Biotehniška fakulteta 0 0 0