The dissertation presents the results of study of antimicrobial and antibiofilm-forming effect of plant-based substances upon opportunistic microorganisms of the oral cavity during dysbacteriosis arisen under inflammatory diseases of periodontium. According to the results of the dissertation work, an integrated approach was developed to the evaluation and correction of the facultative oral microbiota during inflammatory diseases of periodontium and persistence of associations of opportunistic microorganisms, which includes the evaluation of the state of microbiota and of bioflim-forming activity of opportunistic pathogens, and determination of their susceptibility to antimicrobial preparations, phytoseptics, probiotics and oral hygiene care products.
The dissertation also presents results of the study of the microbiota of periodontal tissues affected by chronic periodontitis. Analysis of the obtained results showed the following detection rate of parodonto-pathogen microorganisms: A. actinomycetemcomitans – 42.0%, P. gingivalis – 68.0%, P. intermedia – 55%, T. forsythensis – 75.5%, T. denticola – 63.5%, and С. albicans – 35.0 %. Based on the analysis of aerobic and facultatively anaerobic microbiota, 389 strains of opportunistic microorganisms were isolated from the nidus of the pathological process of parodont tissue. The analysis results showed that only in 19 % cases one dominating representative was isolated. Associations of two and three opportunistic microorganisms were isolated 2.4 and 1.8 times more frequently, respectively. Thereby, associations of opportunistic microorganisms in the structure of microbiota of periodontal tissues affected by periodontitis were persisted in 81 % cases. Most frequently, the associations of opportunistic microorganisms were represented by the following species: S. aureus+E. faecalis, S. aureus+E. coli, S. aureus + E. cloacea, S. aureus+E. faecalis+C. albicans, S. epidermidis+E. cloacea, and others. In the three-member associations, Candida genus microscopic fungi were present in 90% cases. Analysis of the structure of microbial associations under periodontitis showed that in 73 % cases, Staphylococcus genus bacteria were isolated from the nidus of the inflammatory process within the titres of 108 – 1012 CFU/ml. We chose clinical biofilm-forming methicillin-resistant isolates of S. aureus, isolated from patients after antibiotic treatment, and defined the genetic determinants of biofilm formation. The results of chemotaxonomic identification and PCR analysis let us refer the microorganisms to S. aureus species. We identified 7 genes associated with biofilm formation, and established that biofilm-forming methicillin-resistant S. aureus isolates had the following genetic determinants that are currently related with biofilm-forming ability: icaA, icaB, icaC, icaD, icaR, agr, strА.
A compound screening research of antimicrobial activity of extracts of medicinal plants of the flora of the Carpathian region and of essential oils upon opportunistic antibiotic-resistant microorganisms, including isolates of Staphylococcus genus bacteria, was performed; their antibiofilm-forming and antioxidant activity and main biochemical properties were studied. For the first time, antibiofilm-forming properties of Vaccinium vitis-idaea L. leaf ethyl extract; Potentilla erecta L. rhizome ethyl extract; Equisetum arvense L. ethyl extract were revealed.
New approaches to the screening and microbiological evaluation of preparations with potential antimicrobial activity were proposed considering their biofilm destruction ability, based on the use of clinical antibiotic-resistant isolates characterized by biofilm-forming ability with preset genetic determinants as test-cultures. Based on the theoretical generalization of the results of the experimental study of antimicrobial properties of substances of plant origin, a differential approach to the antimicrobial impact upon antibiotic-resistant biofilm-forming bacteria within the structure of microbial associations during oral inflammatory diseases has been substantiated.
