Intestinal bacteria Campylobacter jejuni have been the most common cause of gastrointestinal infections in humans in the European Union since 2005. The main source of C. jejuni infections in humans is the consumption of insufficiently processed poultry meat, unpasteurized milk and contaminated water. This raises the question of how C. jejuni bacteria, which are known to be very sensitive to external environmental conditions, still survive in the environment and cause further food contamination and human infections. Research in recent years indicates the ability of C. jejuni bacteria to survive in biofilms, which enable them to protect themselves from adverse environmental conditions. We hypothesize that preventing the adhesion of C. jejuni bacteria to surfaces, which is the first stage of biofilm formation, could negatively affect all subsequent stages of biofilm formation. In this master's thesis, we evaluated the impact of mutations in genes involved in different stages of biofilm formation. We included: (i) six mutants of bacteria C. jejuni with single mutations in genes involved in different stages of biofilm formation (mutants in genes luxS, kpsM, omp50, csrA, rrpA and rrpB); and (ii) three mutants of bacterial C. jejuni with a double mutation in genes involved in different stages of biofilm formation (luxS and kpsM genes, luxS and omp50 genes, and rrpA and rrpB genes). The results showed an important role of individual genes, especially, genes luxS, csrA and omp50, which therefore represent a potential target mechanism of alternative control strategies over the pathogenic bacteria C. jejuni.
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