Search

Formation of biofilms of microorganisms, including those of Nakaseomyces glabratus, is responsible for the development of local and systemic pathologies in humans and animals. The system of gene expression coordination (quorum sensing) in the representation of signaling molecules allows regulation of the amount and composition of biofilm populations thus expanding the adaptive capacity of microorganisms. In the presence of gingivitis and odontolithiasis clinical signs in dogs, excessive growth of gram-positive yeast microorganisms is a differential sign of the decreased resistance of the digestive system mucous membranes to colonization. Examination of the densitometric and morphometric parameters revealed general patterns of biofilm formation, regardless of the source of Nakaseomyces glabratus isolates. Depending on the time of cultivation of the microorganisms, a gradual increase in the optic density absolute values was established. Intercellular communications were achieved by coaggregation of the heteromorphic structures, which formed clusters with rounded liquid-containing formations detected among them. The population immobilization of the architectonics of the mature three-dimensional biofilm, as consistent with cultivation conditions, was accompanied by the differentiation of numerous cells of different sizes and shapes depending on the stage of the cell cycle. Results of the examination of the general patterns of the heterogeneous micromycete population development are promising for expanding the boundaries of knowledge of the adaptation mechanisms of ubiquitous microorganisms to long-term in vivo and in vitro persistence. Methods for studying morphometric and densitometric indicators avoiding interfering into the natural biofilm architectonics are recommended to optimize the long-term and retrospective mycological studies, as well as to develop effective mycosis treatment and prevention regimens.

Introduction. Clinical strains of microorganisms, including opportunistic yeast-like fungi (YLF) of the genus Candida, are resistant to currently used antifungal drugs. In this regard, the search for alternative ways to potentiate the activity of antimicrobial agents in relation to the infectious agent is an important and relevant area of research. The study of combinations of existing antimycotic drugs and a medicinal extract of plant origin – farnesol – is one of the promising approaches in the fight against resistant strains of YLF genus Candida. In our previous studies, farnesol has been shown to exhibit relative activity against YLF Candida albicans biofilms. In this study, we used 6 clinical isolates and one museum strain YLF C. albicans to study the effect of farnesol on the antifungal activity of antimycotic drugs.Aim. To prove that farnesol can increase the antifungal activity of certain antimycotics.Materials and methods. To determine the sensitivity of 7 strains of YLF C. albicans to the antimycotic drugs "Nystatin" (NYS 50 µg), "Ketoconazole" (KET 10 µg), "Clotrimazole" (CTR 10 µg), "Amphotericin B" (AMB 10 µg), "Voriconazole" (VRC 10 µg) disk diffusion test was used. A solution of farnesol in concentrations of 100, 50 and 25 µM in a volume of 25 µl was applied to the disk with the antimycotic drug. Sterile physiological (PhS) solution was used as a control (pH 7.0; V = 25 µl).Results and discussion. In 34.3 % of of experiments we can talk about the modulating effect of farnesol solutions on the antifungal activity of antimycotic drugs. In all these cases, the sensitivity of YLF C. albicans to the antimycotic drug increases.Conclusion. The results of this study provide useful information for understanding the mechanism of QS-molecules action with antifungal activity, as well as they are the basis for the practical application of some QS-molecules in the treatment of infectious diseases caused by YLF of the genus Candida. The study demonstrates that farnesol can be recommended as an active substance that improves the sensitivity of YLF Candida to antimycotic drugs, especially in the case of multi-resistant strains Candida.

The paper demonstrates morphometric and densitometric parameters of microbial biofilms recovered from lambs with digestive disorders. Changes of quantitative and species composition of the intestinal microbiocenoses in the lambs with digestive disorders were compared with the ones of the clinically healthy lambs. Light microscopy results demonstrated formation of three-dimensional biofilm structure in the form of dense grid consisting of gram-negative and gram-positive bacteria, yeast cells, hyphas and pseudohyphas surrounded with intracellular polymer matrix. Presence of blastospores aided to the increased number of cells attached to the substrate, and biofilm was formed, which consisted of rod and round cells attached to the microfungi cells. In the process of dispersion that occurred during the destruction of the intercellular matrix and bacterial and yeast cell detachment, branched structures separated from the microcolonies and colonized microorganism- free regions of the substrate. The intensity of biofilm formation by the microorganisms under study was evaluated by optic density measurement in 48 hours of cultivation. Fluorescence microscopy results demonstrated that the dynamics of changes of the viable microbial structures was specified by intermittent periods of increased or decreased biofilm formation intensity. Cells characterized by active growth and replication and forming alternating subpopulations were detected in the examined microbial cultures. When determining the viability of the microorganisms in the biofilms, the viable (green fluorescence) and non-viable (red fluorescence) cells were differentiated.

Yeast-like fungi of the genus Candida are causative agents of the infectious pathology of the mucous membrane of the gastrointestinal, respiratory, urogenital tracts and skin of mammals, sepsis, and disseminated infection in birds. The search and testing of multilevel algorithms for biofilm identification when exposed to chemotherapeutic and disinfectant drugs for blocking the synthesis or destruction of the intercellular matrix in the development of superficial, deep and systemic candidiasis of animals are relevant for developing and improving diagnostic and antiepidemic measures. It was established that the formation of biofilm heterogeneous structure comprises multiple stages implementing the processes of intercellular communication due to the synthesis of a polymer matrix composites. Optical microscopy revealed a three-dimensional structure of biofilms in the form of a dense network consisting of yeast cells, hyphal and pseudohyphalic forms surrounded by an intercellular polymer matrix. Candida spp. pathogenicity factors contribute to infection of susceptible species due to adhesion, invasion, secretion of hydrolases, dimorphism. Formation of mono-species or poly-species biofilms of microorganisms, including Candida spp., causes the development of superficial, deep and systemic candidiasis. Detection of a large amount of yeast and micellar phases in C. albicans and C. africana isolates was a differential sign of a significant degree of colonization of the mucous membranes of the larynx, pharynx, and tonsils in case of local and systemic pathologies in pigs. The results of studies of the biofilm heterogeneous structure and phenotypic signs of yeast-like fungi can be used in a comparative study of biological characteristics and the identification of common patterns and differential signs of microorganisms, optimization of mycological diagnostics, and also in the development of antimycotic drugs.

Active use of medical devices in contact with the blood stream has created the need to articulate the testing requirements of such products [1], various methods of modelling and assessment of potential complications. One of the most important aspects of testing such products is to evaluate their direct impact on blood. To obtain objective results of the study any modeling should be as close as possible to the situation of clinical use and reproduce the characteristics of blood flow. And also take into account the possibility of the use of anticoagulants and introducing in the model additional pharmacological preparations if they can influence the biochemical and physical characteristics of blood and their use is inextricably linked to the use of the product. The present article contains the results of the conducted scientific-research and experimental-design works on creation of the device to simulate the conditions of the blood flow to the preclinical testing of experimental samples of materials and devices intended for implantation in the human body for permanent or prolonged contact with blood

Microbiological studies conducted the effectiveness of surfaces decontamination by using potassium iodide submicron aerosol, made by the device Generator of sea air «Aeroiodine». We used bacteria of the genus Staphylococcus as the test cultures. The effectiveness of decontamination was 35±5%.