Phase formation and relaxor properties of lead-free perovskite ceramics on the base of sodium-bismuth titanate

The work was supported by the Russian Foundation for Basic Research (Projects 16-53-48009, 17-03-00542)

Management control – International Observatory 2014

International audienc

The effectiveness of biofilm formation of daily cultures of clinically significant strains of opportunistic bacteria

Background. The formation of biofilm structures by microorganisms living in the hospital environment is a serious medical problem. To conduct correct experimental studies, it is necessary to know the speed and efficiency of biofilm formation by clinically significant species of opportunistic bacteria.   Aim: to study the kinetics of plankton culture growth and the rate of biofilm formation by clinically significant pathogens of infections associated with medical care to substantiate the methodology of further research.   Materials and methods. The strains from the working collection of the Laboratory for Microbiome and Microecology of the Scientific Сentre for Family Health and Human Reproduction Problems were used. Experiments were carried out with conditionally pathogenic microorganisms of the Enterobacteriaceae family and non-fermenting gram-negative bacteria. The optical density was measured, the total microbial number of the cell suspension was determined, and the morphological structure of the biofilm was evaluated using a light microscope on sterile cover glasses for thespecies Pseudomonas aeruginosa, Klebsiella pneumoniae and Serratia marcescens.   Results. The duration of the lag phase of the kinetic curve of cell growth varied in isolates of S. marcescens, P. aeruginosa and K. pneumoniae from 1 to 4 and 6 hours of cultivation, respectively. Despite this, the exponential growth phase was the same for all tested isolates and amounted to 4 hours. Thus, isolates of clinically significant species entered the stationary growth phase after 5–10 hours of cultivation and were characterized as fast-growing. On abiotic surfaces, after 8 hours of incubation of the tested cultures, the initial stages of the formation of biofilm structures were observed, after 20 hours the formed multilayer biofilm was visualized, after 24 hours succession occurred, new single cells were attached to the place of the detached structures.   Conclusion. The data obtained on the duration of the main stages of growth kinetics compared with the visualization of the formation of biofilm structures on abiotic surfaces should be taken into account when studying the effects of disinfectants, antiseptics and antibacterial drugs on planktonic cells and biofilm associations of clinically significant opportunistic microorganisms

Identification of Infectious Diseases Patterns in the Combined Use of Bacteriological Diagnostics and MALDI Biotyper

In multidisciplinary hospitals, there are conditions conducive to the emergence of healthcare-associated infections: high concentration of people with reduced immunity in a limited area, the presence of a significant number of sources of contagion (patients and carriers), a change in the biocenosis of the mucous membranes and skin of patients and medical personnel under the influence of widespread use of antibiotics and cytostatics. The aim of the research was in the intercomparison of the standardized bacteriological algorithms and the MALDI Biotyper system in the microbiological diagnosis of pathogens as illustrated by the healthcare-associated diseases.Materials and methods. Seventy-eight patients of a multidisciplinary hospital of a regional level (Irkutsk) in 2018–2019 were examined. The age of patients ranged from 1 to 15 years. The material for the study was blood, sputum, swabs from the tracheobronchial tree, throat, nose, wound, abdominal fluid, cerebrospinal fluid, and swabs from environmental objects. Identification of the isolated cultures (78 bacterial strains) was  carried out using generally accepted bacteriological methods, as well as using the MALDI Biotyper system.Results and discussions. In the structure of healthcare-associated infections, Pseudomonas aeruginosa occupied a leading position. Not all isolates of microorganisms were identified by standardized bacteriological methods. The identification of strains with characteristic manifestations of physiological and biochemical characteristics was more reliable. Identification difficulties arose in the presence of atypical properties of microorganisms when the use of MALDI Biotyper would be crucial.Conclusion. It is necessary to apply an integrated approach to conduct reliable diagnostics of pathogens. It includes standardized bacteriological methods and methods for identifying microorganisms using mass spectrometry in the subsequent stages

Frequency of strains with multiple antibiotic resistance in the structure of opportunitistic pathogens

Background. The problem of antibiotic resistance has remained significant for the medical community for more than half a century, since the first cases of resistance to penicillin were registered.   The aim. Analysis of the long-term dynamics of changes in the antibacterial resistance of microorganisms and the creation of a collection of multi-resistant strains of opportunistic microorganisms.   Materials and methods. The study included data from 3173 bacteriological samples of various loci of the human body for 2010 and 2020–2021. The sensitivity of isolated cultures was determined by the disk diffusion method to antimicrobial drugs of the following groups: penicillins, cephalosporins, fluoroquinolones, aminoglycosides, carbapenems, tetracyclines, macrolides, lincosamides, oxazolidinones, glycopeptides and others.   Results. In the general structure of conditionally pathogenic microorganisms, a significant increase in the frequency of isolation of multidrug-resistant representatives of the genus Staphylococcus by two or more times was observed in 2021 compared to 2010 and 2020. We also observed a significant increase in the proportion of multidrug-resistant Streptococcus spp. and non-fermenting gram-negative bacteria. These changes marked the beginning of the creation of a collection of conditionally pathogenic microorganisms with multiple antibacterial resistance. In the structure of multiresistant microorganisms included in the “Collection of human microbiota of the Irkutsk region”, the leading positions belong to Klebsiella pneumoniae (23.81 %), Escherichia coli (19.05 %) and Staphylococcus aureus (22.22 %).   Conclusion. Antibiotic resistance monitoring is an important measure to control the resistance of community-acquired and nosocomial (nosocomial) microorganisms both within a particular country and globally

Comparison of the risks of recurrent bleeding from class FI peptic ulcers after topical epinefrine topicle

The purpose of the study is to conduct a systematic review and meta-analysis of current data on the likelihood of relapses after the use of local injections of epinephrine for endoscopic hemorrhage control classes FI according to J.A. Forrest in the upper gastrointestinal tract. An additional goal of this study is to develop a method for extracting relevant information from open literary sources to fill the database of the AI Forrest decision support system.Цель исследования – провести систематический обзор и мета-анализ современных данных о вероятности рецидивов после применения местных инъекций эпинефрина для эндоскопической остановки кровотечения классов FI по J.А. Forrest в верхних отделах желудочно-кишечного тракта. Дополнительной целью данного исследования является отработка метода извлечения из открытых литературных источников актуальной информации для наполнения базы данных системы поддержки принятия решения «AI Forrest» врачом-эндоскопистом

The Magnitude and Mechanism of Charge Enhancement of CH∙∙O H-bonds

Quantum calculations find that neutral methylamines and thioethers form complexes, with N-methylacetamide (NMA) as proton acceptor, with binding energies of 2–5 kcal/mol. This interaction is magnified by a factor of 4–9, bringing the binding energy up to as much as 20 kcal/mol, when a CH3+ group is added to the proton donor. Complexes prefer trifurcated arrangements, wherein three separate methyl groups donate a proton to the O acceptor. Binding energies lessen when the systems are immersed in solvents of increasing polarity, but the ionic complexes retain their favored status even in water. The binding energy is reduced when the methyl groups are replaced by longer alkyl chains. The proton acceptor prefers to associate with those CH groups that are as close as possible to the S/N center of the formal positive charge. A single linear CH··O hydrogen bond (H-bond) is less favorable than is trifurcation with three separate methyl groups. A trifurcated arrangement with three H atoms of the same methyl group is even less favorable. Various means of analysis, including NBO, SAPT, NMR, and electron density shifts, all identify the +CH··O interaction as a true H-bond