Currently, one of the most urgent problems in clinical practice is the antibiotic therapy ineffectiveness at chronic diseases treatment caused by biofilms-forming microorganisms. One of the ways to its solution is the search for new compounds with antibiofilm activity which can prevent the adhesion of microorganisms, disrupt the structure of the biofilm matrix and affect the Quorum sensing system. The aim of the study was to investigate adamantane derivative 1-[4-(1-adamantyl) phenoxy]-3-(N-benzyl,N-dimethylamino)-2-propanol chloride (KVM-97) antimicrobial activity mechanism against Staphylococcus aureus biofilms. Methods. The ability of the adamantane derivative KVM-97 to prevent S. aureus biofilm formation and to destroy previously formed biofilms has been tested on polystyrene plates by gentian violet sorption on these structures, followed by desorption with organic solvent and use of resazurin (redox indicator). The S. aureus cells viability in mature biofilms was evaluated with specific dyes for living (acridine orange) and dead (propidium iodide) cells. Lowry method was used to assess the effect of KVM-97 on the matrix components for the total protein contents determination, the polysaccharides were detected spectrophotometrically (using phenol and sulfuric acid), Bap-protein – by test with Congo red. Persisters’ subpopulation was detected by activation of the SOS response in bacteria when exposed to high concentrations of antimicrobial substances. Results. It was found that KVM-97 (the compound with the adamantyl radical) showed an antibiofilm effect against S. aureus, decreasing biofilm biomass: at the biofilm formation stage – by 22.5% and 75.0%, while in case of 2-day biofilms treatment – by 34.5% and 32.4% at 0.5 MIC and 5.0 MIC respectively. Compound KVM-97 was able to reduce the number of metabolically active S. aureus cells only at the stage of biofilm formation (reduction by 92.7 and 95.8% at 2.0 and 5.0 MIC). Obtained results indicated that this adamantane-containing compound did not affect the protein and polysaccharides contents of S. aureus biofilms matrix. The changes of Bap-protein level caused by KVM-97 were not statistically significant (p>0.05). It was shown that KVM-97 did not prevent the formation of metabolically inactive persister cells; their share was 0.71% of the control. Conclusions. Thus, adamantane-containing compound KVM-97 is able to prevent S. aureus biofilm formation, causing significant biofilms’ mass reduction, as well as lowering the viable cells number in them and destroying already formed biofilms. Its antibiofilm effects are not associated with matrix protein and polysaccharides synthesis impairments. Further thorough investigations are needed to establish the effect of this compound on eDNA synthesis, the Quorum sensing system, and the ica and arg genes expression of S. aureus responsible for biofilm formation.

Synthesis and biological activity of novel adamantane-based dialkylaminopropanol quaternary salts Topicality. The emergence and spread of multidrug-resistant pathogens leads to a decrease in efficacy of antibiotic therapy, causes the duration of patient's hospital stay and increases treatment costs. The screening of potential antimicrobial agents among the new classes of chemical compounds is one of the promising methods to overcome the problem of resistance. Aim. To synthesize and to make screening studies of antimicrobial activity of quaternary salts of adamantane derivatives (3a-3l) with the aim to find of new prospective compound with good activity. Materials and methods. The synthesis and investigation of physicochemical properties of new adamantane-based dialkylaminopropanol quaternary salts were carried out. The evaluation of antimicrobial action against S. aureus, E. coli and C. albicans strains were performed. Results and discussion. The results showed that the inhibitory activities of quaternary salts with 1-adamantylethyl radical in their alkoxy group were significantly higher than those of the compounds with 1-adamantyl and 1-adamantyloxyethyl radicals in their alkoxy group. Conclusions. 3c was the most active compound tested against all strains, with MIC between 1.56 and 3.12 µg/mL, and its antimicrobial activity was similar to that of myramistin.

Arylaliphatic aminoalcohols appeared to be the new promising class of compounds for the development of antibacterial and antifungal agents. The aim of the presented study was to analyze the «chemical structure-antimicrobial activity» relationship for further activity-directed synthesis of compounds of this class. The antimicrobial activity of the compounds was investigated by serial broth dilution method. Primary analysis of the effect of substituents’ structure on the ability of the derivatives to inhibit the growth of test-microorganisms was carried out by empirical method. Molecular structural characteristics of arylaliphatic aminoalcohols (surface area, volume, partition coefficient logP and dipole moment) were calculated by means of «Hyperchem 8.0.8» software. Relationship between the antimicrobial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and molecular characteristics was investigated by correlation analysis using the Spearman test. Statistical processing was performed by «StatSoft Statistica 6.0», the data obtained were evaluated using Chaddock scale. The data obtained suggest, that the presence of both antibacterial and antifungal activity in arylaliphatic aminoalcohols depends on the amino group structure and composition of aryl(alkyl)oxy-radical (4-(1,1,3,3-tetramethylbutyl)phenyl, 1-adamantyl, 4-(1-adamantyl)phenyl, 4-phenyl-phenyl or 2,4-ditretbutyl phenyl). The correlation analysis revealed an inverse relationship between the antimicrobial action and surface area, volume, and lipophilicity of compounds. The tightest correlation was found between these parameters and antistaphylococcal activity. Our results indicate the promises of the synthesis, directed to the reducing of the molecule size and lipophilicity of tetramethylbutylphenyl aminoalcohols, for further development of broad-spectrum antimicrobial agents.