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Gewählte Master / Diploma Thesis:

Bernhard Rauch (2019): Intrinsic bacterial defence mechanisms against biocides in Gram-negative bacteria.
Master / Diploma Thesis - Institut für Lebensmittelwissenschaften, BOKU-Universität für Bodenkultur, pp 93. UB BOKU obvsg FullText

Data Source: ZID Abstracts
Abstract:
Food safety is globally seen one of the most important topics. Even though food safety has developed substantially over the last decades, most currently there are new challenges to be mastered. Due to wrong- and misuse of bactericidal substances bacteria might develop tolerance and resistance mechanism against these substances. The use of widely applied disinfectants like quaternary ammonium compounds (QACs) in sub-lethal concentration led to the formation of persistent microbes, which can resist the general cleaning and disinfection process in food plants. Especially Gram-negative bacteria possess an additional outer membrane with therein-anchored lipopolysaccharides (LPS), which act as an additional defence barrier and presents an opportunity for adaptation. A possible and promising alternative to QACs as disinfectants are ionic liquids (ILs), however so far in detail nothing is known about the influence of LPS on the efficacy of ILs. The aims of this thesis were to find out, how different variations of LPS influence the efficacy of QACs and ILs. Additionally, the formation of tolerances and resistances of bacteria against antibiotics and ILs after exposure of bacteria to sub-lethal concentrations of ILs over a long time period was investigated. In the course of this thesis QACs and ILs showed similar results and that LPS have a major influence on the efficacy of both substance classes. The efficacy did not increase with shorter LPS length but rather a formation of two levels with a breaking point in the outer core region of the LPS was observed. The IL [C10,10MIM][Cl] was proven as a new promising disinfectant being effective in the lowest concentrations and additionally its efficacy was not influenced by LPS. The long-term exposure to sub-lethal concentrations did not show any formation of tolerances or resistance mechanisms against disinfectants or antibiotics.

Beurteilende(r): Domig Konrad

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