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Study of biofilm formation of bacterial isolates from milk and dairy products
Nováková, Veronika ; Demnerová, Kateřina (advisor) ; Seydlová, Gabriela (referee)
Bacterial biofilm is a complex community of microbial cells, which are embed into the extracellular pollysacharide matrix. Typical ability of the biofilm is the ability to adhere to either abiotic, or biotic surfaces. The formation of biofilm is a dynamic process, which finally formes a 3D multicellular complex. The initial phase is called the adhesion. After that process is done, the extracellular polymeric matrix is produced to create living conditions of bacteria in biofilm. Biofilm has hight level of antimicrobial resistance. This resistance consists of physical and chemical barriers, which effectively block diffusion and penetration of antimicrobial substances inside the biofilm. Biofilms cause problems in food industry, where it could be origin of food contaminations. Thefore it is necessary to understand the relationship between microorganisms and materials used in food industry. Key words: biofilm, milk and dairy products, milk and dairy industry, disifectanc, Escherichia coli, Staphylococcus spp.
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Study of biofilm formation of bacterial isolates from milk and dairy products
Nováková, Veronika ; Demnerová, Kateřina (advisor) ; Seydlová, Gabriela (referee)
Bacterial biofilm is a complex community of microbial cells, which are embed into the extracellular pollysacharide matrix. Typical ability of the biofilm is the ability to adhere to either abiotic, or biotic surfaces. The formation of biofilm is a dynamic process, which finally formes a 3D multicellular complex. The initial phase is called the adhesion. After that process is done, the extracellular polymeric matrix is produced to create living conditions of bacteria in biofilm. Biofilm has hight level of antimicrobial resistance. This resistance consists of physical and chemical barriers, which effectively block diffusion and penetration of antimicrobial substances inside the biofilm. Biofilms cause problems in food industry, where it could be origin of food contaminations. Thefore it is necessary to understand the relationship between microorganisms and materials used in food industry. Key words: biofilm, milk and dairy products, milk and dairy industry, disifectanc, Escherichia coli, Staphylococcus spp.
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SCCmec and other mobile genetic elements associated with methicillin resistance in staphylococci.
Kubištová, Lucie ; Lichá, Irena (advisor) ; Plocek, Vítězslav (referee)
Staphylococci are common part of human flora but also they are a dangerous pathogen. Among staphylococci strains, methicillin resistance is widespread. The mecA gene, organized in mec complex, is responsible for methicillin resistance. The mec complex is part of mobile genetic element - staphylococcal chromosome cassette SCCmec. SCCmec is large variable mobile genetic element and it is always composed of three parts - mec complex, ccr complex and J regions. Complex mec consists of mecA gene and its regulatory genes mecR1 and mecI. Complex ccr encodes recombinase genes, they are responsible for excision and insertion of SCCmec. J regions are remaining parts of SCCmec, which include other mobile genetic elements that directly influence methicillin resistance genes expression or carry genes for resistance to other antimicrobial agents. SCCmec or its parts can be transferred by horizontal gene transfer between staphylococci both intraspecific and interspecific, although mechanism of its transfer is still unknown. Eleven types of SCCmec have been described so far. In this thesis, I summarized the findings about molecular composition of SCCmec, horizontal gene transfer of the genes encoding methicillin resistance and molecular evolution of SCCmec. Mobile genetic elements play a key role in evolution and...
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