Stanislav I. Koshechkin

Introduction . Chronic hepatitis C (CHC) in children, typically presents with minimal inflammation, fibrosis, and transaminase elevation. Recently, the gut microbiota has emerged as a key factor driving CHC fibrosis. Aim . To study the bacterial profile of the gut microbiome in young children with CHC. Material and methods . The study included 21 full-term children under the age of 3 with CHC of minimal activity, without prior treatment with direct-acting antiviral drugs. The control group consisted of conditionally healthy children under 3 years of age without liver pathology. Sequencing of the gut microbiota (V3–V4 region of the 16S rRNA gene; primers 341F-801R, Litech, Russia) was performed using the Illumina MiSeq platform (Illumina, USA). Results . Metagenomic analysis revealed the predominance of the numerical composition of Bacillota/Bacteroidota, which make up more than 95% of the bacterial population of the sample. Changes in the intestinal microbiome were found in children with CHC with a minimal degree of activity, including the detection of 67 bacterial species that were absent in children of the control group. Patients with CHC of minimal activity showed an increase in the Bacillota/Bacteroidota ratio index (p = 0.000184). A shift in the percentage ratio and logarithmic indicator (Gram+/Gram−) towards gram-negative flora has been observed; these can have both pro-inflammatory and anti-inflammatory effects, depending on the genus and strain. Quantitative assessment of gram-negative bacteria is of practical importance, as it may indicate an increased endotoxin load and the risk of liver fibrosis in children with CHC. Conclusions . In children with CHC, the composition of the gut microbiota differed across 67 taxa; there was a significant increase in the Bacillota/Bacteroidota ratio index (p = 0.000184) and an increase in the proportion of gram-negative bacteria to 22.3%, which may indicate a risk of bacterial translocation.

Introduction . Early life is a dynamic period for skin microbial colonization and the establishment of local and systemic immunity. The skin microbiota can be notably affected by various factors. Modern approaches to skin care of the infants are based on the principles of pH stabilization, maintaining the skin barrier integrity and optimal microbial diversity. Aim . To evaluate factors contributing to the establishment of skin microbiota and its microbial diversity in early life. Materials and methods . A total of 100 full-term healthy infants were divided into two groups receiving a comprehensive skin care: Group 1 to whom skin care was applied with conventional skin care products, and Group 2 who was treated with natural skin care products. Two samples of forearm skin microbiota were collected from each participant: the first one — on day 1, before using the care products, and the second one — after one-month use of care products. The 16S rRNA gene sequencing method for bacterial identification was used for the study of microbiota. A comparative intergroup analysis of the samples taken before and after the use of skin care products was performed. Results and discussion . Samples were balanced using clinical data, as well as alphaand beta-diversity indices at visit 1. To evaluate skin condition and environmental factors, different data on participants were collected. The results of sample analysis revealed that age may affect the proportions of microorganisms. Other factors such as the presence of siblings, pets, and skin condition had no pronounced effects on the composition of the skin microbiota. During the study, the proportions of the main species did not change from visit 1 to visit to in either group. However, the proportions of the extended set of microorganisms underwent great changes in group 2. Conclusions . A laboratory analysis of samples collected before the use of skin care products showed a relationship between microbiota and age. The skin care products used in the study did not adversely affect the commensal skin microbiota.

Introduction . During the early postnanal life, gut microbiota establishment is an important stage of ontogenesis, which plays a key role in the development and maturation of the child's metabolic and immune systems. Oligosaccharides, which reach a child’s body with the breast milk and have prebiotic and immunomodulatory properties, are critical regulators in the formation of the microbial community. Aim . To assess taxonomic development of the gut microbiota in breastfed and formula-fed infants in the first months of life and interpret the characteristics of its metabolic potential from the perspective of the biological role of breast milk oligosaccharides. Materials and methods. We conducted a prospective, longitudinal, non-interventional, parallel-group cohort study. The study included 90 infants: 45 were breastfed, 45 were formula-fed, receiving a probiotic-containing infant formula supplemented with galactooligosaccharides, and 2'-fucosyllactose. The infants were observed on 30 ± 2, 60 ± 2, and 120 ± 2 days of age. Microbiological tests of stool samples were performed at Visits 1 and 3. After quality control, 126 samples from 64 infants were included in the final test, of which 34 were from breastfed infants and 30 from formula-fed infants. The LEfSe method was employed to identify significantly discriminative taxa between groups. Results. It was found that some statistically significant differences in the composition of the intestinal microbiota were stable between the groups both at 30 days and 4 months of age. These findings confirm that breastfeeding is a key factor for the early establishment of the intestinal microbiota. In its absence, the microbial colonization trajectories, the taxonomic structure, and the nature of interspecies interactions in microbial communities undergo changes. However, the inclusion of prebiotic components in infant formula is a key growth factor for Bifidobacterium. This helps to adjust the trend of development of the gut microbiota, bringing it closer to the breastfed infants’ indicators. Conclusions. As can be seen from the above, feeding type has a marked impact on the early development of the gut microbiota. A formula enriched with 2'-fucosyllactose promotes intestinal colonization by the bacterial genus Bifidobacterium. The increased proportion of these bacteria in formula-fed infants may be considered as an adaptive protective mechanism of the development of microbiota in the absence of breast milk.

Background. The gut microbiota of infants experiences substantial alterations during the initial years of life, which are imperative for immune maturation, nutrient absorption, and metabolic programming. Among various microbial metabolites, short-chain fatty acids (SCFAs), particularly acetate produced by gut bacteria during fermentation of dietary fibers, are critical for regulating interactions between the host and the microbiota. A significant factor influencing the composition and functional capacity of the microbiota in the early months of life is the feeding type. Aim. To assess the influence of breastfeeding on the changes in the intestinal microbiota, specifically the proportion of bacteria capable of synthesizing SCFAs, particularly acetate, during the first four months of life, and to compare these changes with the frequency of pathogen detection. Materials and methods. The study was conducted as part of a prospective longitudinal non-interventional cohort study with parallel groups. Follow-up assessments occurred during the first 4 months of life, with scheduled visits at approximately 30±2, 60±2, and 120±2 days. Participants were categorized into groups based on their feeding type: breastfed (BF) and formula-fed (FF). The composition of the intestinal microbiota, the proportion of SCFA-synthesizing bacteria, and the frequency of pathogenic organism detection were analyzed. Results. The findings indicate that feeding type is associated with variations in taxonomic composition and in the estimated metabolic potential of the intestinal microbiota. In breastfed infants, there was a more favorable progression in the proportion of acetate-producing bacteria. In contrast, in the formula-fed group, there was greater variability in microbial profiles and a lower abundance of potentially protective microbial communities. The observed differences were associated with variations in pathogen detection. Conclusion. The type of feeding during the early months of life significantly impacts the development of the metabolic potential of the intestinal microbiota, representing a crucial factor in early microbial and metabolic adaptation.

Background. It is known that the gut microbial community has a significant impact on the health of the host organism. It has been shown that changes in the composition and metabolic potential of the microbiota occur in people with obesity and diabetes type 2 (T2D). However, the impact of the microbiota on metabolic changes after bariatric surgery remains unclear. Aim. To assess the influence of the gut microbiome composition on metabolic parameters in patients with obesity and T2D after bariatric surgery. Materials and methods. The study included patients with T2D and obesity, who were treated with bariatric surgery (gastric bypass). Before surgery, as well as 6 and 12 months after surgery, the anthropometric, laboratory parameters were measured, feces were collected for analysis of the intestinal microbiota. The microbiota composition was determined through sequencing of the 16S rRNA gene from stool samples. For a subset of patients, the stool metabolome was also studied. Results. After surgery, there was a significant positive trend in weight loss, glycemia, lipid spectrum parameters, and insulin resistance. However, patients did not achieve target levels of 25(OH) vitamin D and calcium. Taxa were identified whose abundance before surgery was associated with the dynamics of parathyroid hormone and vitamin D. The order Verrucomicrobiales was negatively associated with vitamin D dynamics, while the order Fusobacteriales, which includes hydrogen sulfide producers in the gut, was positively associated with the increase in parathyroid hormone. Interestingly, these bacteria were also elevated in patients with higher total cholesterol levels prior to intervention, whereas other H2S producers in the gut correlated with C-peptide levels. No significant associations between the metabolome and clinical parameters' were found; however, the correlation structure of microbiome and metabolome data in patients with obesity was examined. Conclusion. The study revealed an association between several intestinal microbiota species and metabolic parameters after bariatric interventions. These results are pilot and, if reproduced, may allow the prediction of the bariatric surgery effects on weight and glycemia based on the composition of the gut microbiota.

Background. The intestinal microbiota influences the occurrence, course, and outcome of allergic diseases, including those that develop in young children. Aim. To evaluate the effectiveness of the probiotic Acipol® Kid in the treatment of skin and gastrointestinal manifestations of food allergy. Materials and methods. The study included 153 children aged 1–6 months: 122 subjects diagnosed with cow’s milk protein allergy and 31 healthy subjects. Children with allergies were divided into two groups: Group 1 (n = 60) received elimination treatment (mother’s milk-free diet and/or therapeutic formula), and Group 2 (n = 62) received elimination treatment and the probiotic Acipol® Kid containing Lactobacillus rhamnosus ATCC 53103 1 × 109 CFU and Bifidobacterium longum CECT 7894 5 × 108 CFU. Healthy children comprised the comparison group. On Days 1, 45, and 90 of the study, symptoms were assessed, and feces were analyzed for fecal calprotectin on Days 1 and 45. Results. The use of the probiotic Acipol Kid contributed to a 25% reduction in crying frequency, a 76% reduction in the number of children with prolonged crying, and a 26% reduction in intestinal manifestations, as measured by the COMISS index. The probiotic demonstrated high activity against skin symptoms, reducing the severity of lichenification and excoriations by 13% and 9%, respectively, and decreasing intestinal mucosa inflammation by 41%. Conclusions. The use of the probiotic agent Acipol Kid, containing Lactobacillus rhamnosus ATCC 53103 and Bifidobacterium longum CECT 7894, in addition to basic therapy, helps eliminate symptoms in children with severe intestinal and skin symptoms of cow’s milk protein allergy. The obtained data on increasing the biodiversity of commensal microbiota and the potentiating effect on the synthesis of short-chain fatty acids and vitamins B1, B7, and K support considering the biodiversity an important therapeutic factor for the development of healthy intestinal microflora.

Disruption of intestinal homeostasis is a leading factor in the pathogenesis and progression of systemic inflammation in patients with acute severe pancreatitis. The development of systemic complications occurs due to both mesenteric hypoperfusion and dysregulation of intestinal motility, as well as destruction of the intestinal barrier, with translocation of bacterial bodies and their substrates. This increases the risk of developing multiple organ failure and increased mortality. With the advent of high-throughput sequencing methods for microbiome samples, for example, in the 16S rRNA format, the possibilities for studying the structure of microbial communities have expanded significantly. In this regard, there is increasing evidence of the relationship between human health and the microflora inhabiting various parts of the body.AIM OF THE STUDY. Description of the microbiota composition of the initial sections of the small intestine in patients with severe acute pancreatitis.MATERIAL AND METHODS. The study included 7 patients with a diagnosis of severe acute pancreatitis (6 men, 1 woman), the average age was 54.1±14.4 years. Patients were divided into two groups. Group 1 (n=4) included patients admitted on the 2nd–4th day from the onset of a pain attack. Group 2 (n=3) included patients admitted no later than 24 hours from the onset of the disease. The bacterial composition of jejunal swab samples was studied using 16S RNA sequencing. The severity of the condition was assessed using the integral APACHE II, SOFA, SAPS II scales. In patients of the main group, APACHE II was score 22±2.83, SOFA was score 6.8±0.5, SAPS II was score 32.9±6.4, in patients of the comparison group, APACHE II was score 18.0±3.7, SOFA was score 4.0±2.6, SAPS II was score 24.4±5.0.The material was collected at the time of insertion of a sterile multifunctional intestinal catheter behind the Treitz ligament, no later than 6 hours after admission to the intensive care unit. At the time of material collection, the patients did not receive antibacterial therapy or enteral nutrition.RESULTS. More severe disease was associated with reduced representation of Nesseria species in the microbiome mucosa and parvimonas micra, inhabiting the mucosal layer, as well as Megasphaera micronuciformis. The proportion of the genera Streptococcus (species S. rubneri / parasanguinis / australis) and Actinomyces and a number of genera from the Enterobacteriaceae family in such patients was, on the contrary, higher.

Aim. To evaluate the effectiveness of treatment of bacterial vaginosis (BV) with the nifuratel+nystatin complex and its effect on the lactobacillus profile (LBP) in the vagina. Materials and methods. A multicenter, prospective, observational study included 41 patients diagnosed with BV (main group) who were treated with vaginal capsules containing 500 mg of nifuratel and 200,000 IU of nystatin (Macmiror® Complex). Efficacy was assessed at 2 weeks and 4–6 weeks after treatment based on clinical data (absence of pathological discharge). The control group for the comparative assessment of LBP included 25 healthy women. Lactobacillus index (LI, the proportion of lactobacilli in the total bacterial mass) and the abundance of Lactobacillus crispatus, L. gasseri, L. jensenii, and L. iners were assessed using a polymerase chain reaction before treatment with BV, at 2 weeks and 4–6 weeks after the end of therapy, as well as in the control group. Additionally, the vaginal pH level was measured. Results. Clinical recovery was achieved in all main group patients and persisted throughout the observation. In all patients in this group, lactobacilli comprised 0.01–100% of the total bacterial mass. The frequency of lactobacilli species in the control group was relatively uniform, with a relatively uniform abundance of lactobacilli and a slight dominance of L. crispatus, with frequent isolation of two species in samples and high LI (70%) in 80% of females. Before treatment in the main group, the majority of vaginal samples contained one species of lactobacilli; 40% had LI70%, and in 62.5%, L. iners was isolated. LBP did not change significantly within 2 weeks after treatment, and after 4–6 weeks, it became comparable to that in the control group. A decrease in pH was associated with LBP recovery. However, there was no strong correlation between LI and individual species of lactobacilli in samples with or without BV. Conclusion. Nifuratel+nystatin complex is highly effective in BV treatment. The treatment had no adverse effect on LBP, which did not differ significantly immediately after treatment compared to the baseline. However, 4–6 weeks after the treatment, LBP recovered spontaneously, reaching comparable indicators with a group of clinically healthy females regarding species composition and LI.

Background. The oropharyngeal microbiota is involved in the development of colonization resistance, affecting viral adhesion and metabolism. Any deviations in the stability of the environmental microbial niches of the oropharynx alter the local immune response and can trigger severe chronic somatic disorders. Aim. To compare the composition of the microbiota of children during an episode of respiratory infection and healthy volunteers examined in different periods of convalescence. The obtained data can be used to predict the course of the disease, analyze the risk of complications, and assess the frequency of the diseases in the future. Materials and methods. From 20.01.2022 to 23.12.2022, an open-label prospective single-center randomized comparative study was conducted, which included 120 children aged 5-10 who presented with symptoms of acute respiratory infection. The control group consisted of 15 asymptomatic children examined at different periods of convalescence. The study compared changes in the oral microbiota composition of patients and healthy children. The evaluation was performed using complete 16S rRNA gene sequencing on the Oxford Nanopore platform. Taxonometric analysis at the species and genera level was performed using the Knomics-Biota platform. The R programming language was used for statistical processing. In addition, the parameters of α- and β-diversity of the microbiota were assessed. The Chao1 and Shannon indices were calculated to assess α-diversity (diversity within one community). The Chao1 index is based on the number of species found in the sample and also rare species that are found only 1 or 2 times, thus preventing underestimation of diversity. The Shannon index includes both the number of species and their uniformity in the community. A change in the index indicates the dominance of one or more species. The following indicators were used to assess the β-diversity describing the differences between two microbiota samples at the species and genera level: Bray–Curtis dissimilarity (characterizing the ratios of common and different microorganisms between the samples) and the Aitchison distance (reflecting the differences in the proportions of microorganisms). In addition, the balance between the two groups of microorganisms was evaluated using the NearesBalance method, which characterizes the differences between the microbiota of the main and control groups. Results. The results of our study show that during respiratory infection, the state of the oropharyngeal microbiota is characterized by an increase in α-diversity, which is associated with an increase in the proportion of species of Streptococcus salivarius, Streptococcus pneumoniae, Streptococcus pseudopneumoniae, Streptococcus pyogenes, Streptococcus thermophilus and A12 versus the proportion of Streptococcus mitis, Streptococcus oralis, Streptococcus gwangjuense, Streptococcus sanguinis, Streptococcus gordonii and FDAARGOS_192. In the control group, the oropharyngeal microbiota was divided into two clusters. The dominance of streptococci was observed in the first group (control), while the second group had a more uniform representation. Analysis of the changes in microbial communities in the main and control groups can show the stages of oral microbiota recovery after an acute respiratory infection episode. Conclusion. More research is needed in the field of the oropharyngeal microbiome on a larger sample of healthy children, to standardize the communities of the oropharyngeal microbiota, to study the interaction within communities and with the body as a whole. Analysis of the impact of the microbiota on the frequency and course of respiratory infections and the rate of complications opens up new prospects in treating, rehabilitating, and preventing diseases. These research areas can contribute to improving children's health and quality of life and introducing new approaches into clinical practice.

Background. Intestinal microbiota is one of the most important factors determining the state of human health, including its influence on the immunological mechanisms regulating the development of allergic diseases in childhood. The role of intestinal microbiota and the gut – lung axis in the development of bronchial asthma (BA) is an important area of research.Aim. To analyze the taxonomic composition of intestinal microbiota in children with BA using 16S rRNA gene sequencing.Materials and methods. The study included patients with BA (n = 50, mean age 10.34 ± 2.99 years) and a group of apparently healthy individuals (n = 49, mean age 10.3 ± 2.8 years). For all patients, medical history was taken, and physical examination and stool test were performed. Patients with BA were assessed for the level of total and specific immunoglobulin (Ig) E and underwent spirometry. The microbiota composition was analyzed by 16S rRNA gene sequencing with subsequent bioinformatic and statistical analysis.Results. Significant differences in the composition of the intestinal microbiota (beta diversity) and a decrease in taxonomic diversity (alpha diversity) were found in patients with BA compared to healthy controls. The intestinal microbiota of patients with BA was characterized by an increase in the abundance of Bacteroides, Parabacteroides, Lachnospira, Roseburia, Akkermansia, Anaerostipes, Sutterella, Odoribacter, Phascolarctobacterium, Butyricimonas, as well as unclassified bacteria from the Rikenellaceae families. The intestinal microbiota of children without BA was characterized by greater abundance of bacteria from Blautia, Bifidobacterium, Dorea, Ruminococcus, Streptococcus, Eubacterium, Acinetobacter, Collinsella, Lactococcus, Catenibacterium genera and unclassified bacteria from the Clostridiaceae and Coriobacteriaceae families. Significant differences in the quantitative abundance of bacteria were revealed depending on the type of sensitization, the level of total IgE, and the value of FEV1.Conclusion. The results obtained indicate the differences in the intestinal microbiota composition in children with BA and healthy children.