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The aim of this study was to identify and quantify faecal indicator bacteria in blackwater collected from a source separation unit and determine the amount of E. coli isolates resistant to antimicrobials and their potential to produce extended spectrum β-lactamases (ESβLs) and metallo-β-lactamases (MβLs), which hydrolyse the most important antibiotics used in clinical practice. Most of the isolates were resistant to amoxicillin with clavulanic acid (36.4 %), followed by ticarcillin with clavulanic acid (22.7 %) and tetracycline (18.2 %). ESβL-producing genes blaCTX-M and blaTEM were found in three (13.6 %) and four (18.2 %) E. coli strains, respectively, while MβL genes were found in two (9.1 %). By separating at source, this pilot study clearly shows that gastrointestinal bacteria of healthy people can be an important source of antibiotic resistance released into the environment through wastewaters. One way to prevent that is to treat wastewater with a combination of TiO2, UV light, or ozone, as successful methods to remove resistant bacteria and prevent their spread in the environment., V vzorcih črne vode, ki je ena od frakcij odpadne vode, smo ugotavljali prisotnost in število fekalnih indikatorskih bakterij, vključno z bakterijo Escherichia coli (E. coli). Pri osamljenih sevih E. coli smo ugotavljali njihovo odpornost proti izbranim antibiotikom in njihov potencial za tvorbo nekaterih β-laktamaz razširjenega spektra in metalo-β-laktamaz. Preizkušeni sevi so bili najpogosteje odporni proti amoksicilinu s klavulansko kislino (36,4 %), tikarcilinu s klavulansko kislino (22,7 %) in tetraciklinu (18,2 %). Nukleotidne sekvence za blaCTX-M in blaTEM smo našli pri treh (13,6 %) in štirih (18,2 %) sevih, medtem ko smo gene za izbrane metalo-β-laktamaze ugotovili pri dveh (9,1 %) sevih E. coli. Pilotna študija, z ločevanjem odpadne vode na viru nastanka, kaže, da so bakterije v prebavnem traktu zdravih ljudi lahko pomemben vir prenosa odpornosti proti antibiotikom v okolju preko odpadne vode. Eden izmed načinov za preprečevanje širjenja odpornosti proti antibiotikom je čiščenje odpadne vode z uporabo kombinacije TiO2, UV svetlobe in ozona, ki so se pokazale kot uspešne metode za odstranjevanje bakterij, odpornih proti antibiotikom.

Razširjena uporaba antibiotikov je povzročila, da se njihov obseg v okolju dnevno globalno povečuje. Antibiotiki se v telesu ne presnovijo v celoti. Večina antibiotikov se v okolje vnese preko živali, saj se v veterini uporabljajo kot zdravstvena preventiva, za zdravljenje bakterijskih okužb, z namenom pospeševanja rasti in/ali prirasta živali, preostanek pa v okolje vnesemo ljudje, zaradi zdravljenja bakterijskih okužb. Vnos antibiotikov v okolje neposredno najbolj vpliva na vodne organizme, predvsem pa je vse bolj skrb vzbujajoč pojav odpornih bakterij oz. superbakterij. Te bakterije so odporne proti antibiotikom in posledično nanje antibiotiki ne delujejo več, zato je vse več še pred kratkim preprosto ozdravljivih bakterijskih okužb težje ozdravljivih oz. neozdravljivih. Odstranjevanje antibiotikov je torej nujno. Zaradi vstopa večine antibiotikov v vodno okolje, se osredotočamo predvsem na odstranjevanje iz odpadnih vod. Konvencionalne komunalne čistilne naprave antibiotikov niso sposobne odstraniti in posledično lahko ti preprosto vstopijo v površinske vode, podtalnico in tudi pitno vodo. Za odstranjevanje antibiotikov iz odpadnih vod se vse bolj uporabljajo napredni oksidacijski procesi. Namen magistrske naloge je bil primerjava različnih naprednih oksidacijskih procesov za čiščenje odpadnih vod, ki vsebujejo antibiotike in preveritev, ali so ti postopki primerni za odstranjevanje antibiotikov iz vodnega okolja. Preučevali smo naslednje tehnike oz. postopke: direktna ozonacija, ozonacija pri povišanem pH (pH=9,5), ozonacija pri povišanem pH (pH=9,5) ob dodatku H2O2, ozonacija, katalizirana z dodatkom Fe2+, ozonacija, katalizirana z dodatkom Fe2+ in UV svetlobe, ozonacija s Fentonovo oksidacijo in ozonacija s foto-Fentonovo oksidacijo. Učinkovitost tehnik smo ovrednotili s spremljanjem celotnega organskega ogljika (TOC) in kemijske potrebe po kisiku (KPK). Ugotovili smo, da pri vseh postopkih proces poteče dvostopenjsko z bolj učinkovito prvo stopnjo procesa. Direktna ozonacija se je izkazala za najmanj učinkovito od vseh preučevanih postopkov, tako glede na TOC, kot KPK rezultate. Učinkovitost ozonacije se je povečala ob povišanem pH, ob dodatku UV, H2O2 in/ali katalizatorjev. Najučinkovitejša je bila ozonacija s foto-Fentonovo oksidacijo, s katero smo dosegli med 83 in 96 % stopnjo oksidacije prisotnih antibiotikov, ter med 65 in 84 % stopnjo mineralizacije, torej popolno razgradnjo antibiotikov v anorganske komponente, CO2 in H2O. S tem smo potrdili, da so napredni oksidacijski procesi primerni postopki za odstranjevanje antibiotikov iz odpadnih vod. The widespread use of antibiotics has been causing increase of their extent in the environment. Antibiotics are not completely metabolised in the body. Most antibiotics come into the environment through animals, as they are used in the veterinary medicine for health prevention, for the treatment of bacterial infections, with the purpose to promote growth and/or animal increment. The rest come to the environment because of human consumption, due to the treatment of bacterial infections. Antibiotics into the environment directly affect the aquatic organisms, and above all, the increasing concern arouses phenomenon of resistant bacteria or superbacteria. These bacteria are resistant to antibiotics and, consequently, they are not affected by them, so nowadays more and more bacterial infections are more difficult to be cured or are even incurable. Therefore, the removal of antibiotics is necessary. Due to the entry of most antibiotics in the aquatic environment, their removal from wastewater is the most important. Conventional municipal wastewater treatment plants are not capable of removing antibiotics and thus they can easily enter surface water, groundwater, and even drinking water. The main focus nowadays is the addition of the tertiary cleaning using advanced oxidation processes. The purpose of this thesis was to compare the various advanced oxidation processes for wastewater treatment containing antibiotics and verification if these procedures are suitable for the removal of antibiotics from the aquatic environment. We studied the following experimental techniques/procedures: direct ozonation, ozonation at elevated pH (pH = 9.5), ozonation at elevated pH (pH = 9.5) at the addition of H2O2, catalysed ozonation by addition of Fe2+, catalysed ozonation by addition of Fe2+ and UV light, ozonation with Fenton oxidation and ozonation with photo-Fenton oxidation. The methods were evaluated according to the total organic carbon (TOC) and chemical oxygen demand (COD). It can be concluded that studied procedures occur in two phases with first stage of process to be more effective. Direct ozonation was the least effective in terms of TOC, as well as COD. The efficiency of the ozonation increased at elevated pH, with the addition of UV, H2O2 and/or catalysts. The most effective procedure was ozonation with photo-Fenton oxidation, where we achieved between 83 and 96% oxidation of the present antibiotics and between 65 and 84% mineralization, hence the complete decomposition of antibiotics into inorganic components, CO2, and H2O. Our results confirmed that advanced oxidation processes are appropriate for removing antibiotics from wastewater.

Zaradi neustrezne in nekritične uporabe protimikrobnih zdravil (PZ) pri živalih, ki vstopajo v prehransko verigo človeka, število odpornih bakterijskih sevov, osamljenih iz živali, kakor tudi živil, narašča. Kampilobakterioza, ki jo povzroča Campylobacter jejuni je ena izmed najpogosteje prijavljenih gastrointestinalnih bolezni pri ljudeh, večja prevalenca odpornih bakterijskih sevov pa povečuje tveganje za neučinkovito zdravljenje bolezni. Zato je pomembno na ta problem opozarjati vse deležnike živilske proizvodno-oskrbovalne verige in tudi zdravnike, da se redno izvajajo testi bakterijske odpornosti na najpomembnejša protimikrobna zdravila (PZ). V eksperimentalnem delu smo določali odpornost 8 sevov C. jejuni iz proizvodnega (klavniškega) in 8 sevov iz naravnega (površinskih voda) okolja proti šestim PZ (eritromicinu, ciprofloksacinu, tetraciklinu, gentamicinu, nalidiksni kislini in streptomicinu) na komercialno pripravljenih mikrotitrskih ploščicah SensititreTM EUCAMP2. Tako klavniški (KS) kot vodni (VS) sevi so pokazali odpornost proti istim vrstam PZ – ciprofloksacinu (CIP), tetraciklinu (TET) in nalidiksni kislini (NAL). Delež odpornih sevov proti posameznim PZ je bil višji pri klavniških (CIP 87,5 %, TET 50 %, NAL 50 %) kot vodnih (CIP 25 %, TET 12,5 %, NAL 25 %) sevih. Zasledili smo tudi večkratno odpornost, ki je bila pri klavniških sevih 87,5 % pri vodnih pa 25 %, in sicer med CIP in TET (KS: 37,5 %), ter CIP in NAL (KS: 50 %, VS: 25 %). Prišli smo do sklepa, da je vzrok večje odpornosti KS večja izpostavljenost PZ, vzrok odpornosti VS pa je verjetno prenos odpornih sevov iz klavnice v njeno okolico. Due to inadequate and uncritical use of antimicrobial drugs in animals, entering the human food chain, the number of resistant bacterial strains, isolated from humans as well as from the food, is increasing. Campylobacteriosis caused by Campylobacter jejuni is one of the most frequently reported gastrointestinal diseases in humans. The appearance of resistant bacterial strains increases the risk of ineffective treatment of the disease. Therefore, it is important to alert all stakeholders in the food production and supply chain, as well as doctors, to regularly carry out bacterial resistance tests on the most important antibiotics. In our experimental work, we tested the resistance of 8 strains of C. jejuni from the production (slaughterhouse) and 8 strains from the natural (surface water) environment against six antimicrobial drugs (erythromycin, ciprofloxacin, tetracycline, gentamicin, streptomycin nalidixic acids) on commercially prepared microtiter plates SensititreTM EUCAMP2. Both slaughtering (SS) and water (WS) strains have shown resistance to the same groups of antibiotics - ciprofloxacin (CIP), tetracycline (TET) and nalidixic acid (NAL). The proportion of resistant strains against individual AM was higher in slaughterhouse (CIP 87,5 %, TET 50%, NAL 50%) than water (CIP 25 %, TET 12,5 %, NAL 25 %) strains. Multidrug resistance was also present, which is in the case of slaughterhouse strains 87,5 % and 25 % in water strains, namely between CIP and TET (SS: 37,5 %) and CIP and NAL (SS: 50 %, WS: 25 %). We have come to the conclusion that the cause for the higher resistance levels of SS might be a higher exposure to antibiotics, and the cause of resistant WS is the transfer of resistant strains from the slaughterhouse to its surroundings.