Vpliv strukture biofilma na delovanje protimikrobnih sredstev

Baš, Sara (author), Stopar, David (mentor), Kramer, Mateja (comentor)

Biofilmi so združbe mikroorganizmov, ki so pritrjene na površino ali pa se pojavijo na različnih interfazah. Predstavljajo velik problem, njihovo odstranjevanje je težavno in povzroča velike stroške v industriji zlasti v primeru, ko se pojavijo v ocevju. Osredotočili smo se na vpliv okolja na tvorbo biofilma in delovanje protimikrobnih sredstev v odvisnosti od strukture biofilma. Spreminjali smo tip površine in hranila (vir ogljika in minimalno/bogato gojišče), v katerih smo gojili biofilme. Za ugotavljanje razlik med tvorjenimi biofilmi smo biofilme na površinah mikroskopirali in merili reološke značilnosti nastalih biofilmov. Strukturno najbolj različna biofilma smo tretirali z različnimi nekomercialnimi in komercialnimi protimikrobnimi sredstvi ter primerjali odstotek mrtvih celic v biofilmih po tretiranju. Pri gojenju biofilmov smo vzpostavili pogoje, ki so omogočali nastanek vertikalnega gradienta pokritosti površine z biofilmom. Pokritost površine z biofilmom je bila odvisna od tipa površine in vira ogljika. Ugotovili smo, da nobeno protimikrobno sredstvo ni v celoti uničilo vseh celic v biofilmu. Učinkovitost biocidov se je z večanjem pokritosti površine z biofilmom manjšala. Rezultati nakazujejo, da je učinkovitost biocidov odvisna od reoloških lastnosti biofilma. Podobno kot v biofilmu smo tudi v planktonski obliki opazili anikorelacijo med gostoto bakterijske kulture in učinkovitostjo biocida.

• Language: Slovenian
• Keywords: biofilmi, bakterijski biofilmi, Escherichia coli, planktonske celice, tvorba biofilma, površine, steklene površine, PMMA, kristal violet, odstranjevanje biofilma, reološke lastnosti, protimikrobna sredstva
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: BF - Biotechnical Faculty
• Publisher: [S. Baš]
• Year: 2017
• PID: 20.500.12556/RUL-96392
• UDC: 579.24.083+579.26:579.842
• COBISS.SI-ID: 4822136
• Publication date in RUL: 30.09.2017

BAŠ, Sara, 2017, Vpliv strukture biofilma na delovanje protimikrobnih sredstev [online]. Master’s thesis. S. Baš. [Accessed 30 March 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=96392

Secondary language

• Language: English
• Title: Effect of biofilm structure on effectivness of antimicrobials

Abstract

Biofilms are groups of microorganisms which are attached to the surface or which occur at different interphases. They represent a big problem because they are difficult to remove, and they cause significant costs in the industry if they occur in the pipework. In this thesis, we focused on the impact of the environment on the formation of biofilms and the effect of their structure on the effectiveness of antimicrobial agents. We used different types of surfaces and nutrients (different carbon sources and minimum/rich media) in which we have grown biofilms. We used microscopy and rheology to determine viscosity and elasticity of resulting biofilms. We treated the most structurally different biofilms with various non-commercial and commercial antimicrobials and compared the percentage of dead cells in the biofilm after treatment. While growing biofilms, we have established the conditions which enabled the formation of the vertical gradient of the biofilm covered surface. Biofilm covered surface was dependent on the type of surface and carbon source. We saw that agents that we used didn’t completely destroy all the cells in the biofilm. The effectiveness of antimicrobials was decreasing whenever the biofilm surface coverage was increased. It seems that the effectiveness of biocides depends on the rheological properties of the biofilm. Similarly to the biofilm, we observed that in planktonic form there is some kind of anticorrelation between the density of the bacterial culture and the effectiveness of the biocide.

• Keywords: biofilms, bacterial biofilms, Escherichia coli, planktonic cells, biofilm formation, surfaces, glass surfaces, PMMA, cristal violet, biofilm removal, rheological properties, antimicrobials