[Assessment of species diversity of anaerobic intestinal microbiota in children and adolescents with exogenous constitutional obesity].

The problem of the increasing obesity among children and adolescents is urgent. One of the most interesting and promising directions in this area is to study the correlation of individual microorganisms with the presence and absence of obesity. The aim of the study was to assess the correlation between the isolation frequency of individual microorganisms and the presence of obesity in children and adolescents and to identify possible associations between different groups of microorganisms in obese patients. Material and methods. 156 male and female patients aged from 7 to 17 years were included in the study. The patients were divided into a control group (n=23) (healthy patients), a group of children with exogenous constitutional obesity without complications (n=25), a group of children who had one or more complications of obesity (n=108). For all patients body mass index (BMI) was calculated. Additional examination included a cultural study of the intestinal microbiota. Fecal samples of patients were used as the material. Preparation of the material for inoculation, inoculation and subsequent incubation of the Petri plates were carried out under anaerobic conditions. The isolated microorganisms were identified using the MALDI-ToF mass spectrometry method. Results. When analyzing the correlation between obesity and individual taxa, statistically significant differences were obtained only for Bifidobacterium spp. (p=0.045). The analysis of the correlation between obesity and the isolation of individual microorganisms has shown that Bifidobacterium pseudocatenulatum (p=0.012), Candida albicans (p=0.012), Streptococcus salivarius (p=0.016), Bifidobacterium breve (p=0.003), Veillonella parvula (p=0.013), Haemophilus parainfluenzae (p=0.003), Streptococcus oralis (p=0.001), Weissella confusa (p=0.036), Enterococcus mundtii (p=0.036) were isolated less often in patients with obesity than in control group. Conclusion. The results of the study has demonstrated that only one taxon, Bifidobacterium spp., had a significant correlation with the absence of obesity. At the same time, a reliable correlation with the absence of obesity was also established for individual microorganisms, including several microorganisms from Bifidobacterium spp. and Streptococcus spp., which may enable to establish certain microbiological predictors of obesity and its complications.

[The interactions along the microbiota-gut-brain axis in the regulation of circadian rhythms, sleep mechanisms and disorders]. / Rol' vzaimosvyazei po osi mozg­kishechnik­mikrobiom v regulyatsii tsirkadiannykh ritmov, mekhanizmakh sna i ikh narushenii.

The bidirectional relationship between cerebral structures and the gastrointestinal tract involving the microbiota embraces the scientific concept of the microbiota-gut-brain axis. The gut microbiome plays an important role in many physiological and biochemical processes of the human body, in the immune response and maintenance of homeostasis, as well as in the regulation of circadian rhythms. There is a relationship between the higher prevalence of a number of neurological disorders, sleep disorders and changes in the intestinal microbiota, which actualizes the study of the complex mechanisms of such correlation for the development of new treatment and prevention strategies. Environmental factors associated with excessive light exposure can aggravate the gut dysbiosis of intestinal microflora, and as a result, lead to sleep disturbances. This review examines the integrative mechanisms of sleep regulation associated with the gut microbiota (the role of neurotransmitters, short-chain fatty acids, unconjugated bile acids, bacterial cell wall components, cytokines). Taking into account the influence of gut dysbiosis as a risk factor in the development of various diseases, the authors systematize key aspects and modern scientific data on the importance of microflora balance to ensure optimal interaction along the microbiota-gut-brain axis in the context of the regulatory role of the sleep-wake cycle and its disorders.

[The significance of glymphatic pathway in the relationship between the sleep-wake cycle and neurodegenerative diseases]. / Rol' glimfaticheskogo klirensa v mekhanizmakh svyazi tsikla «son­bodrstvovanie¼ i razvitiya neirodegenerativnykh protsessov.

Selective and progressive death of neurons is a characteristic feature of the process of neurodegeneration and leads to corresponding neuronal dysfunctions. Neurodegenerative diseases represent a heterogeneous group of clinically distinct disorders with similar molecular mechanisms of pathogenesis. They are based on the processes of abnormal aggregation of proteins, the formation of fibrillary insoluble structures and their deposition in the form of histopathological inclusions in the tissues of the nervous system. Disturbance of homeostatic functions that regulate neuronal ion and energy metabolism, biosynthesis and degradation of proteins and nucleotides, chronic hypoxia and the penetration of toxic and inflammatory substances into the brain from the bloodstream not only cause metabolic changes associated with age and disorders in the sleep-wake cycle, but also contribute to the development of neurodegenerative diseases. In animal studies, clearance pathways have been identified in which solutes and specific tracers are excreted perivascular into the meningeal lymphatics. The glymphatic pathway promotes the removal of metabolites, including Aß amyloid and tau protein, from the parenchymal extracellular space of the brain. The glymphatic system is discussed to be more efficient during natural sleep, and fluid dynamics through this pathway exhibit daily fluctuations and are under circadian control. This review systematizes the key aspects and scientific data of recent studies on the role of the glymphatic pathway and astroglial AQP-4 as its main determinant in maintaining homeostatic fluid circulation in the brain in normal and pathological conditions, in particular in relation to the regulatory role of the sleep-wake cycle and in development of neurodegeneration.

[The significance of the glymphatic pathway in the relationship between the sleep-wake cycle and neurodegenerative diseases]. / Rol' glimfaticheskogo klirensa v mekhanizmakh vzaimosvyazi tsikla «son­bodrstvovanie¼ i razvitiya neirodegenerativnykh protsessov.

Selective and progressive death of neurons is a characteristic feature of the process of neurodegeneration and leads to corresponding neuronal dysfunctions. Neurodegenerative diseases represent a heterogeneous group of clinically distinct disorders with similar molecular mechanisms of pathogenesis. They are based on the processes of abnormal aggregation of proteins, the formation of fibrillary insoluble structures and their deposition in the form of histopathological inclusions in the tissues of the nervous system. Disturbance of homeostatic functions that regulate neuronal ion and energy metabolism, biosynthesis and degradation of proteins and nucleotides, chronic hypoxia and the penetration of toxic and inflammatory substances into the brain from the bloodstream not only cause metabolic changes associated with age and disorders in the sleep-wake cycle, but also contribute to the development of neurodegenerative diseases. In animal studies, clearance pathways have been identified in which solutes and specific tracers are excreted perivascular into the meningeal lymphatics. The glymphatic pathway promotes the removal of metabolites, including Aß amyloid and tau protein, from the parenchymal extracellular space of the brain. The glymphatic system is discussed to be more efficient during natural sleep, and fluid dynamics through this pathway exhibit daily fluctuations and are under circadian control. This review systematizes the key aspects and the data of recent research on the role of the glymphatic pathway and astroglial AQP-4 as its main determinant in maintaining homeostatic fluid circulation in the brain in normal and pathological conditions, in particular in relation to the regulatory role of the sleep-wake cycle and in development of neurodegeneration.

Evaluation of the influence of the analytical characteristics of the microbiological blood study in bacteremia in a multidisciplinary hospital.

The culture method continues to be the "gold" standard for microbiological diagnosis of bloodstream infections. This is primarily due to the fact that the definition of the etiology of a generalized infectious process determines the etiotropic antibiotic therapy. To do this, it is necessary to conduct periodic microbiological monitoring of the prevailing microflora. To do this, in the present study, a retrospective analysis of the results of a microbiological blood test for sterility was performed in case of suspected bloodstream infections in a multidisciplinary hospital to assess the influence of analytical stage factors on the laboratory data obtained. Automatic hematological cultivators were used, identification was carried out based on the biochemical characteristics of microorganisms, as well as using time-of-flight mass spectrometry with matrix-activated laser desorption / ionization (MALDI-TOF MS). More than 10,000 research results were analyzed, the average microflora seeding rate was 15.1%. The analysis of the isolated microflora was carried out in 2 groups of positive results: at the beginning, the data obtained in the presence of growth in two vials at once were evaluated, then the positive results of blood cultures obtained in any one vial from a pair were studied. The predominance of gram-positive flora in the structure of microorganisms isolated from whole blood was revealed, the influence of cultivation conditions and the composition of thenutrient medium on the isolated flora was not found, however, a number of microorganisms, due to the specific characteristics of metabolism, were characterized by growth under strictly defined cultivation conditions. The presented study actualizes the need for constant microbiological monitoring in order to determine the prevailing hospital microflora, which can contribute to a timely response in order to limit the spread of highly virulent, aggressive, resistant strains of microorganisms leading to the development of generalized bloodstream infections.

Microflora of sputum and autopsy material of patients with COVID-19.

The rapid spread of a new coronavirus infection in the country actualizes the conduct of bacteriological studies of clinical material obtained from the respiratory tract of patients with COVID-19. During the experiments, 230 sputum samples and 260 autopsy lung samples from patients with COVID-19 were analyzed. 946 high-risk strains were isolated and identified by MALDI-ToF mass spectrometry on a Microflex LT instrument (Bruker®). According to the results of bacteriological cultures of sputum, a predominance of gram-positive ones was revealed, amounting to 50.5% (222 strains) of the total number of isolated pathogens. However, falling into this group is manifested by natural representatives of the microflora of the human mucous membranes from the genera Streptococcus, Rothia and Lactobacillus (109 strains in total), which can be manifested by the detection of improper sputum collection, causing contamination by the substance of intense salivation and nasopharyngeal discharge. In turn, the "classic" gram-positive causative agents of pneumonia were detected much less frequently: S. aureus in 5 cases, S. pneumoniae in 6 patients. The causative agents in the order Enterobacterales are represented by 42 strains, among which the most likely species are K.pneumoniae (27 strains). In the group of non-fermenting gram-negative bacteria, A. baumanii (29 strains) prevailed, and P. aeruginosa was also identified in 2 cases. When analyzing the results of a microbiological study of autopsy material (lungs) of patients with COVID-19, significant differences in the qualitative and quantitative composition of the microflora were revealed, compared with sputum. In the group of gram-positive bacteria, 15 strains of the natural microflora of the mucous membranes were identified, while sensitive species dominated among gram-negative pathogens: K. pneumoniae (102 strains), A. baumanii (75 strains), P. aeruginosa (11 strains). Regular microbiological monitoring is essential for antibiotic therapy and prevention of secondary bacterial infection. In the event of a fatal outcome, the results of microbiological analysis of autopsy material can determine the cause of death of the patient.

Characteristics of Stenotrophomonas maltophilia isolates from cystic fibrosis patients in Russia.

Stenotrophomonas maltophilia is a common opportunistic microorganism and an important respiratory pathogen in cystic fibrosis (CF). The aim of this study was to determine antimicrobial resistance phenotypes, sequence-types (ST) and genetic determinants of antibiotic resistance in S. maltophilia strains recovered from CF patients in Russia. S. maltophilia isolates recovered from 170 CF patients were analyzed. Minimum inhibitory concentrations of antibacterial agents were determined using Sensititre Gram Negative GNX2F plates and the results were interpreted according to Clinical and Laboratory Standards Institute (CLSI) criteria. Whole-genome sequencing (WGS) was performed on MGISEQ-2000 platform. SPAdes software, Galaxy, ResFinder, Integrall and PubMLST were used for analysis of WGS data. S. maltophilia strains were identified from 24/170 (14%) CF patients. In total, 25 isolates were detected, two strains were isolated from the same patient. The isolates belonged to 17 different STs, including 5 new STs; ST4 was the most prevalent ST. Resistance to ceftazidime was observed in 60% of strains, to ticarcillin-clavulanate - in 32%, to levofloxacin - in 24%, to trimethoprim/sulfamethoxazole - in 12% of strains. All isolates were susceptible to minocycline. All ST4 isolates were resistant or intermediate to ceftazidime and ticarcillin-clavulanate. In two isolates, the sul1 gene was detected. In one isolate, sul1 was part of a class 1 integron. The detected integron also contained the blaGES-7 and aac(6')-Ib-cr genes. The ST4 sequence-type was the most prevalent ST among S. maltophilia strains recovered from CF patients in Russia. Antibiotic resistance genes, including sul1, blaGES-7, aac(6')-Ib-cr, were detected in single strains.

[Evaluation of the species diversity of microflora isolated from the epithelium of the oral mucosa in patients using removable orthopedic structures based on dental implants]. / Otsenka vidovogo raznoobraziya mikroflory, vydelennoi s epiteliya slizistoi obolochki polosti rta, pri ispol'zovanii s"emnykh ortopedicheskikh konstruktsii s oporoi na dental'nye implantaty.

OBJECTIVE: To assess the species diversity of microorganisms isolated from the oral mucosa in patients with removable orthopedic structures based on dental implants. MATERIALS AND METHODS: The indicators of the species diversity of microorganisms isolated from the oral mucosa in patients of the main and control groups were studied. RESULTS: For prosthetic treatment of patients from main group we used a method of manufacturing an overlapping, frame prostheses supported by teeth and dental implants. The results turned out to be reliable for opportunistic microorganisms Streptococcus anginosus and representatives of the orange periodontopathogenic complex Streptococcus constellatus. CONCLUSION: Microbiological assessment indicates the effectiveness of prosthetic treatment and the use of Corega tablets.

Genome features and antibiotic resistance of Pseudomonas aeruginosa strains isolated in patients with cystic fibrosis in the Russian Federation.

Cystic fibrosis (CF) is a common genetic disease, manifested by airway obstruction and chronic respiratory infection. The most prevalent infectious agent in airways of CF patients is Pseudomonas aeruginosa. This study aimed to determine sequence-types, antimicrobial resistance phenotypes and genes defining adaptive antibiotic resistance in P. aeruginosa isolates recovered from CF patients in Russia. In total, 84 P. aeruginosa strains from 64 CF patients were analyzed. Susceptibility to antibiotics was determined by disk diffusion test. Whole-genome sequencing (WGS) was performed on MGISEQ-2000 platform. SPAdes software, Galaxy, ResFinder, PubMLST were used for analysis of WGS data. Examined P. aeruginosa isolates belonged to 53 different sequence-types (STs), including 6 new STs. High-risk epidemic clone ST235 (10%) and clonal CF P. aeruginosa strains ST17, ST242, ST274 (7%) were detected. Non-susceptibility to ticarcillin-clavulanate, cefepime, imipenem was observed in 63%, 12% and 25% of isolates, respectively; to tobramycin - in 24%, to amikacin - in 35%; to ciprofloxacin, levofloxacin - in 35% and 57% of strains, respectively. Multidrug-resistant phenotype was detected in 18% of isolates. In examined strains, genes of beta-lactamases VIM-2 (5 ST235 strains), VEB-1 (two ST2592 strains), GES-1 (1 ST235 strain), PER-1 (1 ST235 strain) were found. Ciprofloxacin-modifying enzyme CrpP gene was detected in 67% of isolates, aminoglycoside-modifying enzymes AAD, ANT, AAC genes - in 7%, 4%, 12% of strains, respectively. P. aeruginosa isolates from CF patients in Russia demonstrate a high clonal diversity, which is similar to other P. aeruginosa infections. The isolates of high-risk clone and clonal CF P. aeruginosa strains are detected.

General characteristics, features of cultivation and antibiotic resistance representatives of mycobacterium fortuitum group representatives (review of literature).

Recently, more and more scientific works have been devoted to non-tuberculous mycobacteria, both by domestic and foreign researchers. One of the main reasons for this is the increase in patients with immunosuppression of various origins, improvement of the quality of laboratory and instrumental diagnostics of mycobacteriosis. This article focuses on the representatives of the M. fortuitum group, as the main pathogens among the group of fast-growing mycobacteria. The data on the modern classification based on the use of molecular genetic studies are indicated. The M. fortuitum group includes: Mycobacterium fortuitum, M. peregrinum, M. senegalense, M. porcinum, M. houstonense, M. neworleansense, M. boenickei, M. conceptionense, M. septicum, M. alvei. According to the new data, mycobacteria were divided into 5 clades (Abscessus-Chelonae, Fortuitum-Vaccae, Terrae, Triviale, Tuberculosis-Simiae), and based on molecular genetic studies, new genera in the Mycobacteriaceae family were isolated: Mycolicibacter spp., Mycolicibacillus spp., Mycolicibacillus spp., Mycobacteroides spp., Mycolicibacterium spp. In accordance with the new classification, representatives of the Mycobacterium fortuitum group belong to the genus Mycolicibacterium. The main epidemiological features of the main sources of the spread of mycobacteria, factors and ways of their transmission are indicated. Due to their wide distribution in the environment, representatives of the M. fortuitum group are capable of causing diseases of the pulmonary and extrapulmonary localization. The distinctive features of pathogenicity factors, due to which the course of the disease is determined, are noted. The article also indicates the main difficulties and features of determining the sensitivity to antimicrobial chemotherapy drugs, provides data on the main features of antibiotic resistance of M.fortuitum group. In preparing the review, literature sources obtained from international and domestic databases were used: Scopus, Web of Science, Springer, RSCI.