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V naši raziskavi smo analizirali 132 ESBL-pozitivnih izolatov E. coli, vzorčenih pri 66 bolnikih iz Osrednjeslovenske regije in izoliranih na Inštitutu za mikrobiologijo in imunologijo Medicinske fakultete Univerze v Ljubljani. V raziskavo smo vključili izolate bolnikov, pri katerih je bila ESBL-pozitivna E. coli najprej osamljena iz nadzorne kužnine, kasneje pa iz krvi. Z metodo ERIC-PCR smo izolate uvrstili v 33 skupin z različnimi ERIC-profili. Z analizo filogenetskih skupin po Clermontu smo ugotovili, da se 78,8 % izolatov iz hemokultur in 75,8 % izolatov iz nadzornih kužnin uvršča v filogenetsko skupino B2. V 53 % primerov (35) je bil izolat iz nadzorne kužnine enak izolatu iz krvi, od teh pa je bilo 80,6 % E. coli ST131. Zanimalo nas je, kakšna je genotipska razlika med izolati, ki kolonizirajo črevesje in niso vir za bakteriemijo ali sepso, ter izolati, ki jih najdemo v črevesju in krvi. Za slednje izolate so statistično značilni: gen za aerobaktin (82,3 %), kapsularni gen kpsMTII (82,3 %), zapis za avtotransporter sat (84,2 %), genotoksin usp (69,4 %) ter zapisa za adhezine iha (69,4 %) in afa/dra (40,3 %). Na podlagi prisotnosti teh genov bi z genotipizacijo črevesnih izolatov lahko odkrili tiste, pri katerih je tveganje za razvoj težje potekajočih izvenčrevesnih okužb z ESBL-E. coli zaradi lastnosti samega bakterijskega izolata, večje. In our study, we analyzed 132 isolates of ESBL-positive E. coli sampled from 66 patients form Central Slovenian region and isolated at the Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana. Patients isolates were included in the study if the first ESBL-positive E. coli was isolate from surveillance sample followed by a blood culture isolate at a later date. Using the ERIC-PCR method, we were able to distinguish 33 different ERIC profiles. At the same time, we found that 78,8 % of isolates from blood cultures and 75,8 % of isolates from surveillance samples belonged to phylogenetic group B2. 53 % of patients (35) had genetically the same isolate in surveillance samples and blood cultures, of which 80,6 % were E. coli ST131. We compared the genotypes of isolates in surveillance samples, which were not the cause of bacetiemia or sepsis with isolates from hemocultures. We found statistically significant presence of the aerobactin operon (82,3 %), the capsule gene kpsMTII (82,3 %), the autotransporter gene sat (74,2 %), the genotoxin gene usp (69,4 %) and the adhesin genes iha (69,4 %) and afa/dra (40,3 %) in the nonclonal isolates from bloodstream infections. The presence of these genes in rectal isolates could be used to predict a higher risk of developing serious extraintestinal ESBL-E. coli infections based on genetic characteristics of the colonizing isolate.

Proti antibiotikom odporne bakterije predstavljajo enega izmed glavnih zdravstvenih problemov 21. stoletja, še posebej bakterije z geni za encime ESBL in karbapenemaze. K razvoju in širjenju odpornosti proti antibiotikom vplivajo tako človeški, živalski kot okoljski rezervoarji. V Sloveniji je malo znanega o prisotnosti bakterij z zmanjšano občutljivostjo za antibiotike v izvenbolnišničnem okolju, še predvsem na odlagališčih. Namen naloge je bila osamitev bakterij, ki so fenotipsko odporne proti betalaktamom z razširjenim spektrom delovanja in karbapenemom, iz površinskih in podzemnih vod, povezanih z izbranim odlagališčem odpadkov ter genotipska opredelitev fenotipske odpornosti, ki temelji na izločanju encimov za betalaktamaze z razširjenim spektrom delovanja (ESBL) in karbapenemaz. Bakterije iz vzorcev podzemnih in površinskih vod smo osamili z uporabo 3 izbranih selektivno diferencialnih gojišč in jih identificirali z metodo MALDI TOF. Encime ESBL in karbapenemaze smo najprej potrdili s fenotipskimi testi (metoda kombiniranih diskov za potrditev ESBL in CIM testi), nato s tržno dostopnimi kiti določili njihove gene. Ugotovili smo, da so izolati iz površinskih vod odporni proti več antibiotikom, kot izolati iz podzemnih vod. S pomočjo molekularnih testov smo določili gene za odpornost proti betalaktamom pri dveh izolatih, ki smo ju izolirali iz površinskih vod. Pri prvem izolatu Klebsiella oxytoca (ZZV20-11045), izoliranem iz površinskih padavinskih vod, smo potrdili gen za encim CTXM-1 in gen za encim OXA-48. Pri drugem izolatu Pseudomonas aeruginosa (ZZV20-11064), ki smo ga izolirali iz površinskih izcednih vod pa smo potrdili prisotnost gena za encim iz skupine VIM. Iz površinskih voda smo osamili več proti betalaktamom in karbapenemom odpornih bakterij kot v podzemnih vodah. Pri obeh odpornih mikroorganizmih smo potrdili prisotnost genov za encime iz skupine ESBL in karbapenemaze (dokazali smo gene blaVIM, blaCTXM-1 and blaOXA-48). Antibiotic resistance is one of the major health problems of the 21st century. The development and spread of antibiotic resistance is influenced by human, animal and environmental reservoirs. Little is known in Slovenia about the presence of bacteria with reduced sensitivity to antibiotics in the non-hospital environment. Among the major resistant bacteria that pose a threat to human health are bacteria with genes for the enzymes ESBL and carbapenemase. The aim of the study was to isolate bacteria that are phenotypically resistant to betalactams with extended spectrum and carbapenem from surface and groundwater associated with the selected landfill and genotypic definition of phenotypic resistance based on the secretion of enzymes for betalactamase (ESBL) and carbapenemases. Bacteria from groundwater and surface water samples were isolated by three specific selective-differential media and identified using MALDI-TOF. ESBL enzymes and carbapenemases were first confirmed by phenotypic tests (combined disk method to confirm ESBL and CIM tests), then their genes were determined by commercially available kits. Surface water isolates were found to be resistant to more antibiotics than groundwater isolates. Molecular tests confirmed the presence of resistance genes in two isolates isolated from surface waters. In the case of Klebsiella oxytoca isolate (ZZV20-11045) isolated from surface rainwater, the gene for the enzyme CTXM-1 and the gene for the enzyme OXA-48 were confirmed. In the isolate of Pseudomonas aeruginosa (ZZV20-11064), which was isolated from surface leachate, the presence of the gene for the enzyme from the VIM group was confirmed. More betalactam and carbapenem resistant bacteria were isolated from surface waters than in groundwater. In both resistant microorganisms, the presence of genes for ESBL and carbapenemase enzymes were confirmed (genes blaVIM, blaCTXM-1 and blaOXA-48 were detected).

Betalaktamski antibiotiki so najpogosteje uporabljana skupina antibiotikov za zdravljenje bakterijskih infekcij, vendar je problematičen pojav odpornosti nanje. Najpomembnejši mehanizem bakterijske odpornosti je njihova sposobnost sinteze encimov betalaktamaz, ki katalizirajo hidrolizo betalaktamov do neaktivnih produktov. Ker se bakterijska odpornost na antibiotike iz leta v leto povečuje, postajajo možnosti za zdravljenje okužb vse bolj omejene. Zato je ključnega pomena odkrivanje novih protimikrobnih učinkovin in učinkovin, s katerimi bi lahko premostili omenjene mehanizme odpornosti. Monociklični betalaktami so dokazano slabši substrati za betalaktamaze in v nekaterih primerih so na njih delovali zaviralno. Ti dve lastnosti sta pri reševanju problematike z betalaktamazami posredovane bakterijske odpornosti zaželeni, zato so omenjene molekule zanimive za načrtovanje novih zdravilnih učinkovin. Odločili smo se, da bomo v okviru naše magistrske naloge poskusili sintetizirati nove predstavnike te skupine betalaktamskih antibiotikov. Pripravili smo 2-oksoazetidin-1-il-sulfonate z žveplovim substituentom na C4 mestu betalaktamskega obroča. Najprej smo s pomočjo oksidativne ciklizacije ?,?-nenasičenega O-acil hidroksamata, sintetizirali osnovni betalaktamski obroč. Tu smo se srečali z izjemno nizkimi izkoristki, zato smo poskušali optimizirati najbolj težavno, tretjo sintezno stopnjo. Pred uvedbo žveplo vsebujočega substituenta na C4 mesto, je bila za stabilnost produkta nujna zamenjava zaščitne skupine na 1N-OH položaju. Na C4 mesto smo uvedli tri tiole (tiazol-2-tiol, 1-metil-1H-imidazol-2-tiol in 1H-1,2,4-triazol-3-tiol). Na koncu je sledila še ponovna zamenjava skupine na 1N-OH mestu, kamor smo vezali tosilno skupino. Uspelo nam je sintetizirati en končni produkt 2-oksoazetidin-1-il-sulfonatov (2-okso-4-((tiazol-2-iltio)metil)azetidin-1-il 4-metilbenzensulfonat). V ostalih dveh primerih smo sintezo zaključili v sedmi sintezni stopnji. Identiteto izoliranih produktov smo preverili z jedrsko magnetno resonanco (1H in 13C), masno spektrometrijo visoke ločljivosti, masno spektrometrijo, IR spektrometrijo in v primeru trdnih spojin tudi z določitvijo talilnega intervala. Beta lactam antibiotics are the most commonly used family of antibacterial compounds. Nowadays we are facing an acute problem of bacterial resistance to them, the most common and problematic mechanism being their new-found ability to produce beta lactamases. Beta lactamases are enzymes which catalyse the hydrolysis of beta lactam antibiotic and render them inactive. Because bacterial resistance to antibiotics is growing every year, the possibilities for treatment of bacterial infections are getting more and more limited. Therefore the discovery of new antimicrobial drugs and substances which could overcome mentioned mechanisms of resistance are of key importance. Monocyclic beta lactams are poor substrates for beta lactamases and have in some cases even shown to have beta lactamase inhibitory properties. These two qualities are desirable in solving the problem of beta lactamases mediated resistance. Therefore monocyclic beta lactams represent an interesting field of investigation in pharmacy and we decided that in our thesis we will try to synthetize some new representatives of antibacetrially active monocyclic beta lactams. We have synthetized 2-oxoazetidine-1-yl-sulfonates with thiol substituents on C4 position of beta lactam ring. With the help of oxidative cyclization of ?,?-unsaturated O-acyl hydroxamate, we first synthetized substituted beta lactam ring. Here we found ourselves with extremely low yields and have tried to optimize the most problematic, third stage of the synthesis. Before the introduction of thiol substituent on C4 position of beta lactam ring, we had to change the protection group on 1N-OH position of beta lactam ring in order to obtain a proper stability of appropriately C4 substituted products. On C4 position we have introduced three thiol substituents (thiazole-2-thiol, 1-methyl-1H-imidazole-2-thiol, 1H-1,2,4-triazole-3-thiol). In the end we changed the 1N-OH moiety, introducing tosyl group. We managed to prepare one representative of 2-oksoazetidin-1-ilsulfonates (2-oxo-4-((thiazol-2-ylthio)methyl)azetidin-1-yl 4-methylbenzenesulfonate). In other two cases the synthesis stopped at the seventh reaction stage. We have confirmed the identity of the final compounds with nuclear magnetic resonance (1H in 13C), high resolution mass spectrometry, mass spectrometry, IR spectroscopy and in case of solid compounds we also measured the melting points.