The thesis is devoted to the study of biological mechanisms of biofilm formation of S. epidermidis strains under different culture conditions and their influence on the development of experimental features dysbacterioses. A comparative study of the manifestation of pathogenicity factors: hemolytic, lipase, letsytinase activity and ability to adhere in film-forming and non-film-forming strains of S. epidermidis. Studying pathogenicity factors of the film-forming strains it was found that complete hemolysis and lipase activity shown was by all the film-forming strains of S.epidermidis, letsytinase activity was observed in 80%. Among the non-film-forming strains complete hemolysis and lipase activity were observed in 89% and letsytinase - 71%. Researched non-film-forming and film-forming strains of S. epidermidis showed the ability to adhere to buccal epithelial cells of humans. Found that all the film-forming strains of S.epidermidis were hight level adgesion, the index of adhesion of microorganisms was equal to 9,75. It was found that among non-film-forming strains of S. epidermidis were low- (29,40%), medium- (52,90%) and hight (17,60%) level adgesion. Index of adhesion non-film-forming strains of S. epidermidis is 3 times lower compared to the index of adhesion of the film-forming strains of human epithelial cells and was 3,2. Increasing, the studied parameters of biofilm growth by replacing the culture medium occurred within 5 days and for stationary culture conditions - for 3 days. Observed reduction in the number of viable cells in 60000000 times of the biofilm on the 5th day for stationary culture conditions, compared with that of biofilm, formed by replacing the nutrient medium. Established, that biofilm formation occurred in the pH range 5,0-8,0, with maximum growth observed at pH 7,0. The maximum increase in the growth of the studied parameters were observed at pH 7,0 - number of cells was 2,1 ? 109 cells / ml, the biofilm index (ВІ) - 5,6. On the 3 day of cultivation the number of cells in the biofilm of S. epidermidis by pH 5,0 was lower in 19000 times, ВІ lower in 3,5 times, for pH 6,0 - 512 times, BI - 1,3, for pH 8,0 - 100 times, BI - 1,4 compared to the number CFU/ml biofilms that formed in medium with pH 7,0. The best influence on biofilm formation of S. epidermidis was affected by content of 2,0% glucose in the culture medium- number of cells after 3 days of cultivation was 2,3?1011 CFU/ml, which is 26 times higher than the number of cells in the control biofilm. The content of sucrose in the culture medium is higher than 1,0%, and galactose and lactose is higher than 0,5% - caused inhibition of biofilm formation. The most of biofilm-forming strains were susceptible of fluoroquinolones drugs, such as ofloxacin and levofloxacin. It is shown, that when adding fluoroquinolones to daily biofilm in the minimal inhibitory concentration (MIC) of 10 and 50 was inhibited the growthing of biofilm, and 100 MIC - led to its degradation. Adding to daily biofilm 100 MIC of ofloxacin caused a decrease in cell number to 42000 time, compared with the control. For the first time was studied that the development of experimental models of dysbacteriosis, factor of which was biofilm-forming strain of S. epidermidis, that characterized by a decrease in anaerobic lactobacilli - 165 and microaerophilic - 16,5 times, against the backdrop of a pronounced increase in the content of staphylococci - 40000 time, while related aerobes: anaerobes was 1: 98. Whereas, in dysbacteriosis, caused by non-film-forming strain of S. epidermidis, was reduction of anaerobic lactobacilli - in 2,0 time and microaerophilic one in 1,8 times, increasing the content of staphylococci in 6,9 times, while related aerobes: anaerobes was 1: 67. Key words: biofilm, biofilm-forming and non-film-forming strains, biofilm formation, Staphylococcus epidermidis
