Relevance. Acute rheumatic fever (ARF) and chronic rheumatic heart disease (CRHD) remain important medical and social problems despite a declining prevalence in most developed countries. These conditions are late complications of group A streptococcal infection and are associated with chronic valvular heart disease, disability, and premature mortality. Current evidence indicates persistent regional disparities in disease distribution and possible underestimation of the true disease burden.

Aim. To assess long-term trends in the incidence, prevalence, and mortality of ARF and CRHD in the Russian Federation and Moscow during 2012–2024 and to evaluate age-specific and territorial characteristics of disease distribution.

Materials and Methods. A retrospective descriptive epidemiological study was conducted. Data were obtained from Federal Statistical Reporting Forms No. 12 and No. 14. Analyses were performed for the total population and for the following age groups: children aged 0–14 years, adolescents aged 15–17 years, adults aged ≥ 18 years, working-age population, and older-than-working-age population. Incidence, prevalence, and mortality rates per 100,000 population, average long-term rates (ALR), average annual growth rates (AAGR), and trend significance coefficients (t) were calculated. Time-series analysis was performed using the least-squares method with trend-line construction.

Results. A total of 24,815 cases of acute rheumatic fever (ARF) and 110,255 newly diagnosed cases of chronic rheumatic heart disease (CRHD) were registered in the Russian Federation between 2012 and 2024. A statistically significant decline in the main epidemiological indicators was observed. The incidence of ARF decreased 4.3-fold, from 1.76 to 0.41 per 100,000 population (AAGR = -9.6 %; p < 0.001). The incidence of CRHD decreased 1.8-fold, from 7.31 to 4.09 per 100,000 population (AAGR = -6.2 %; p < 0.001), while the prevalence of CRHD decreased 2.0-fold, from 130.88 to 66.06 per 100,000 population (AAGR = -5.8 %; p < 0.001). Mortality from ARF decreased 9.7-fold, from 0.03 to 0.003 per 100,000 population, whereas mortality from CRHD decreased 1.8-fold, from 1.09 to 0.60 per 100,000 population. The highest ARF incidence (ALR = 5.06 per 100,000 population), CRHD incidence (ALR = 13.67 per 100,000 population), and CRHD prevalence (ALR = 194.68 per 100,000 population) were observed in the North Caucasian Federal District. The highest ARF incidence was recorded among adolescents aged 15–17 years (ALR = 3.62 per 100,000 population), whereas CRHD predominantly affected individuals older than working age, with average long-term incidence and prevalence rates of 8.27 and 210.53 per 100,000 population, respectively. In Moscow, the main epidemiological indicators of ARF and CRHD were lower than the national averages and also demonstrated statistically significant declines over the study period.

Conclusion. A decrease in the incidence, prevalence, and mortality associated with ARF and CRHD was observed in the Russian Federation and Moscow during 2012–2024. However, pronounced territorial disparities and age-related differences in disease distribution persist. These findings highlight the need for further improvement of epidemiological surveillance, prevention of group A streptococcal infection and its complications, and early detection of post-streptococcal diseases.

Relevance. Despite the fact that mumps has been a vaccine-preventable infection for many years, it continues to be an urgent public health problem. Epidemiological surveillance and vaccine prophylaxis for mumps are carried out comprehensively together with measles and rubella. At the same time, mumps is given much less attention than measles and rubella.

Aim: to assess the epidemic situation of mumps in the world and in the Russian Federation, the coverage of vaccination, revaccination and the timeliness of their implementation in Russia. To compare the incidence of mumps, measles and rubella.

Materials and methods. A retrospective epidemiological analysis of the incidence of mumps in the world for the period 2012–2024 was carried out in comparison with the incidence of measles and rubella, as well as in the Russian Federation for the period 2007–2024, taking into account the distribution of the incidence of mumps and the structure of cases by age group. The coverage of preventive mumps vaccinations for the period 2012-2024 and the timeliness of vaccination for the period 2021–2024 in the Russian Federation are analyzed. The sample was taken from the World Health Organization database and from the federal statistical observation forms (No. 2, No. 6). The reliability of the differences was assessed using confidence intervals.

Results. The analysis showed that the incidence of mumps in the world and in the Russian Federation differs from the incidence of measles and rubella. In particular, the incidence increases do not always coincide, there are cyclical features and there are differences in the most epidemiologically significant age groups. The incidence of mumps in Russia, although at low numbers, tends to increase (the average annual growth rate is 7.8 %). The highest incidence rate is observed in the group of children aged 3–6 years (3.19 ± 0.22 per 100 thousand. of the corresponding population group), while the lowest incidence rate is in the group of children under 1 year of age (0.5 ± 0.17 per 100 thousand of the corresponding population group). It should be noted that the measles incidence rate is the highest in the group of children under 1 year of age. At the same time, the incidence of mumps among children under 1 year of age is growing at the highest rate of incidence (an increase rate of 4.6 %). The largest contribution to the structure of cases is made by groups of children aged 7–14 years and 3–6 years, the proportion of the total number of cases is 20.3 % and 19.9 %, respectively. The coverage of preventive vaccinations in the Russian Federation decreased against the background of the pandemic and by 2024 has not yet reached pre-pandemic values, while it should be noted that coverage is achieved only by 24 months. Revaccination coverage in 2023 and 2024 amounted to 71.27 % and 92.3 %, respectively.

Conclusion. The presence of an upward trend in the incidence of mumps, high levels of morbidity in children aged 3–6 and 7–14 years, as well as the greatest contribution of these age groups to the structure of cases indicate a worsening epidemic situation for this infection. To a certain extent, the reasons for the deterioration of the epidemic situation are late vaccination and insufficient vaccination coverage. At the same time, differences in the incidence of mumps from the incidence of measles and rubella require consideration of changing approaches to epidemiological surveillance and prevention of mumps.

Relevance. Pneumococcal infection remains one of the common causes of morbidity and mortality worldwide, including among at-risk adults and the elderly. Vaccination is the most effective preventive measure. However, vaccination coverage among at-risk adults in the Russian Federation remains insufficient, which may be related, among other factors, to low public awareness about the possibility of immunization and to low physician adherence to pneumococcal vaccination. At present, data on this indicator in Russia are limited.

Aim. To assess physician adherence to pneumococcal vaccination among at-risk adults.

Materials and Methods. A sample-based prospective observational epidemiological study was conducted, comprising four data collection phases (2019, 2021, 2023, 2025). Data were collected using an anonymous questionnaire. Physicians specializing in the treatment, prevention, and counseling of high-risk adult patients for pneumococcal infection (internists, general practitioners, pulmonologists, cardiologists, endocrinologists, etc.) were invited to participate. Invitations were sent using the database of the National Association of Specialists in Control of Infectious and Non-Infectious Diseases (NASСI). A total of 27,082 respondents participated (8,695 in 2019, 9,032 in 2021, 4,305 in 2023, and 5,050 in 2025). Representatives from 79 out of 85 federal subjects participated in 2019 and 2021, 66 out of 89 in 2023, and 70 out of 89 in 2025. Statistical analysis employed descriptive statistics. Correlation analysis was performed to identify associations between adherence to vaccination and pneumococcal vaccination coverage in specific risk groups, with a significance level of p < 0.05.

Results. In 2025, 64.3 % [CI: 63–65.6 %] of physicians reported recommending pneumococcal vaccination. Between 2019 and 2021, this indicator decreased from 64.4 % [CI: 63.4–65.4 %] in 2019 to 58.6 % [CI: 57.6–59.6 %] in 2021. Vaccination was recommended to patients with chronic bronchopulmonary diseases by 91.1 % of physicians overall [CI: 90.4–91.8 %], including 96.7 % [CI: 93.8–99.6 %] of pulmonologists, 92.7 % [CI: 91.6–93.8 %] of internists, and 91.7 % [CI: 89.4–94 %] of infectious disease specialists. For individuals aged ≥ 60 years, 81.8 % [CI: 80.8–82.8 %] of physicians overall recommended vaccination, including 90.5 % [CI: 81.6–99.5 %] of geriatricians, 75.6 % [CI: 71.9–79.3 %] of general practitioners, and 71.1 % [CI: 69.2–73 %] of internists. Approximately half of physicians recommended vaccination to patients with chronic cardiovascular diseases (62.0 % [CI: 60.7–63.3 %] overall; 67.4 % [CI: 62.3–72.5 %] among cardiologists) and endocrine diseases (56.8 % [CI: 55.5–58.1 %] overall; 77.0 % [CI: 72.4–81.6 %] among endocrinologists). The smallest proportion of specialists (less than one quarter) reported recommending pneumococcal vaccination to patients with chronic kidney disease (15.0 % [CI: 14.1–15.9 %] overall; 44.9 % [CI: 31–58.8 %] among nephrologists), liver disease (17.8 % [CI: 16.8–17.8 %] overall), and immunocompromised patients (24.9 % [CI: 23.8–26.0 %] overall; 84.8 % [CI: 72.6–97 %] among hematologists, 60.3 % [CI: 56.3–64.3 %] among infectious disease specialists, and 38.6 % [CI: 32.8–44.4 %] among oncologists). From 2019 to 2025, the proportion of physicians recommending vaccination to individuals aged ≥ 60 years increased by 21.8 %, and to patients with chronic cardiovascular diseases by 19.9 %. Less pronounced growth was observed for patients with endocrine diseases and workers in occupations harmful to the respiratory system (by 7.1 % and 8.4 %, respectively). The proportion of physicians recommending vaccination to individuals in special living conditions (e.g., shift workers), immunocompromised patients, and patients with chronic liver or kidney diseases did not increase and remained low. A direct, strong, statistically significant correlation was found between the level of vaccination adherence in 2023 and 2025 and the increase in pneumococcal vaccination coverage among at-risk adults (r = 0.77, p = 0.005 and r = 0.72, p = 0.013, respectively). A direct, statistically significant correlation of moderate strength was found between adherence in 2023 and vaccination coverage in 2023 (r = 0.59, p = 0.021).

Conclusion. Further efforts are needed to improve physician awareness regarding pneumococcal vaccination, specifically: incorporating detailed information on specific prophylaxis into clinical guidelines for managing high-risk patients, including immunization strategies, schedules, timing, and efficacy data; expanding the list of individuals eligible for vaccination under the National Immunisation Schedule and the Vaccination Schedule for Epidemic Indications; and actively involving in educational activities on immunoprophylaxis those clinicians who treat high-risk patients and prevent infectious diseases among them.

Introduction. Bronchial asthma (BA) is a heterogeneous disease whose development involves not only genetic predisposition but also important non-hereditary factors, including comorbid conditions such as type 2 diabetes mellitus (T2DM) and metabolic syndrome. The shared pathogenetic mechanisms based on chronic inflammation suggest the existence of common genetic determinants, which remains understudied.

Purpose. To identify molecular genetic markers and risk factors for predisposition to adult-onset BA associated with metabolic disorders.

Materials and Methods. A retrospective case-control study was conducted on a sample of 315 individuals (63 BA patients and 252 conditionally healthy controls), matched for age and sex. Alongside the analysis of concomitant pathology, an association analysis was performed for polymorphisms in the genes: ADRB2 (rs1042713), IL6 (rs1800795), HLA-DQ2.5 (rs2187668), SLC30A8 (rs13266634), and TCF7L2 (rs12255372). Statistical analysis was performed using the χ² criterion in the StatTech v. 4.12.1 program (developer – StatTech LLC, Russia).

Results. BA patients had a significantly higher prevalence of diabetes/metabolic syndrome-associated disorders (11.1 % vs. 4.0 %, p = 0.034) and diagnosed colitis (14.3 % vs. 3.6 %, p = 0.003). Strong associations with BA were found for polymorphisms in genes key to metabolism: SLC30A8 rs13266634 (C/C genotype: 41.3 % vs. 11.5 %, p < 0.001) and TCF7L2 rs12255372 (G/G genotype: 47.6 % vs. 14.3 %, p < 0.001). No associations were found for polymorphisms in the ADRB2, IL6, and HLA-DQ2.5 genes. Research limitations. The retrospective design and the relatively small sample size, which preclude establishing causal relationships.

Conclusion. The obtained data indicate the existence of a "metabolically-associated" phenotype of adult-onset BA, whose pathogenesis is significantly linked to polymorphisms in the SLC30A8 and TCF7L2 genes and corresponding comorbidity. The results justify the expediency of mutual screening of BA patients for metabolic disorders and inflammatory bowel diseases.

Relevance. Achieving and sustaining measles control requires optimization of vaccination schedules that account for demographic changes, immunity dynamics, and infection transmission patterns. A comparative assessment of the long-term effectiveness of different immunization schedules using modern modeling techniques is a relevant scientific and practical task.

Objective. To conduct a comparative assessment of the long-term epidemiological effect of different measles vaccination schedules using the developed agent-based simulation model.

Materials and Methods. A spatially implicit agent-based stochastic model was developed, integrating modules for demography, migration, maternal and vaccine-induced immunity, and age-specific spatial contacts. In a series of 100-year simulations for a population of 100,000 agents, three scenarios were compared: a standard twodose schedule (SRN: 12 months and 6 years), a schedule with an earlier first dose (SR9: 9 months and 6 years, strict timeliness window), and a schedule with a booster dose (SR3: 12 months, 6 and 18 years). The analysis focused on the long-term average incidence, inter-epidemic intervals, and the age distribution of cases.

Results. The SR9 scenario demonstrated a statistically significant 2.5-fold reduction in the long-term average incidence compared to the baseline SRN scenario. SR9 was associated with longer inter-epidemic intervals (6.12 years vs. 5.75 years for SRN), a twofold reduction in peak incidence, and smoother outbreak dynamics. The age distribution of cases showed a significant reduction in incidence both among children under one year and among adults (18+) in the SR9 scenario compared to SRN and SR3. The introduction of a booster dose (SR3) did not lead to a significant reduction in long-term average incidence compared to the standard schedule.

Conclusions. Optimization of the vaccination calendar involving an earlier administration of the first dose (9 months) combined with strict control over vaccination timeliness can provide a more significant and sustained reduction in measles incidence compared to standard or extended booster schedules. The obtained results highlight the importance of refining the age at vaccination initiation and regulating the timing of vaccine administration as key factors for long-term epidemiological control.

Aim. To analyze long-term trends and age-specific patterns of S. sonnei and S. flexneri incidence in the Russian Federation over the period 2009–2024.

Materials and methods. A retrospective analysis was conducted using data from the federal statistical surveillance (Form No. 2 «Information on infectious and parasitic diseases») for 2009–2024. Incidence rates were calculated per 100,000 population. Average annual incidence rates (AAIR) were computed as arithmetic means of annual values. The average annual rate of decline (increase) in incidence (AAR) was estimated from the linear regression coefficient to assess long-term trends. Statistical significance of differences was evaluated using Student's t-test, and confidence intervals were calculated by the Wald method.

Results. The incidence of both shigellosis forms continued to decline, but the pace slowed down: for S. flexneri, AAR changed from -25.8 % (2003–2009) to -12.6 % (2009–2024); for S. sonnei, from -17.4 % to -11.6 %. Since 2022, the incidence of S. sonnei has for the first time significantly exceeded that of S. flexneri (previously S. flexneri had dominated for many years). Over the study period, the epidemic process of S. flexneri was characterized by a lack of pronounced cyclicity and a persistent shift of the highest incidence towards the youngest age groups (children under 1 year and 1–2 years; AAIR 14.11 and 17.69, respectively), indicating a predominantly contact-household transmission route. In contrast, S. sonnei showed regular periodic rises every 2–4 years, with peak incidence in children aged 3–6 years (AAIR 10.38); the proportion of cases among children aged 7–14 years was high (22.1 %).

Discussion. The identified shift in the ratio of pathogens (predominance of S. sonnei since 2022) is consistent with international data and may be considered a marker of improved sanitary and hygienic conditions. The decline in incidence in 2020–2021 is attributed to anti-epidemic measures implemented during the COVID-19 pandemic. The parallel dynamics of S. flexneri incidence among children under 2 years of age and adults indirectly indicates a predominantly familial (contact-household) mode of transmission under current conditions of centralized water supply, whereas the distinct dynamics observed among children aged 3–6 and 7–14 years point to the role of organized groups in the spread of S. sonnei.

Conclusion. Divergent changes were identified in the age structure and incidence ratio of S. sonnei and S. flexneri shigellosis, particularly pronounced in the post-pandemic period (since 2022).

Relevance. Vaccination remains the most effective measure for controlling pertussis spread; however, immunization strategies may require revision in light of changing disease patterns.

Aims. To identify current trends in pertussis incidence in the Russian Federation and propose modifications to vaccination strategies.

Materials and methods. The study was based on analysis of statistical forms "Data on infectious and parasitic diseases" (Form No. 2) and "Data on populations of children and adults vaccinated against infectious diseases" (Form No. 6) for 2013–2025, as well as medical records of 535 infants who experienced pertussis during their first year of life in Moscow in 2023–2025.

Results. Pertussis incidence in the Russian Federation demonstrates a sustained upward trend (average annual growth rate: 9.79 %), with infants under one year remaining the most vulnerable group, accompanied by an increase in pertussis-related mortality. Against this background, a substantial proportion of cases occurs among population groups most frequently serving as sources of infection for infants: during the study period, children aged 7–14 years accounted for 33–44 % of cases, while the share of adult cases increased (17 % nationally and 31 % in Moscow in 2025), substantiating the need for national implementation of age-targeted booster vaccination. The unfavorable epidemiological situation is exacerbated by delays in infant immunization (coverage < 50 % by the end of the first year of life) and low adherence to series completion among children following natural infection (among children who experienced pertussis in 2023, only 11.2 % continued immunization; in 2024 — 50.7 %; in 2025 — 7.6 %).

Conclusions. To stabilize the situation, critical measures include: implementation of booster vaccination for school-aged children; mandatory maternal immunization to provide transplacental protection to newborns; and strict adherence to completion of vaccination series for children following pertussis infection.

Relevance. The population of both the world and the Russian Federation is decreasing every year, including due to a decrease in the birth rate. The upcoming demographic "failure" will undoubtedly affect all aspects of people's lives. According to several studies, the overall decline in the birth rate is also caused by the high prevalence of infertility among both women and men.

Aim. Conduct a descriptive epidemiological retrospective study of the incidence and prevalence of male and female infertility within the Russian Federation (RF) and its individual federal districts in 2011–2024.

Materials & Methods. The study used data from the Form № 12 «Information on the number of diseases registered in patients living in the medical facility's service area» in 2011–2024, as well as data on the quantity of adult population from Rosstat's statistical bulletins «Population of the Russian Federation by Gender and Age» in 2011–2024. The study population consisted of men aged 18–59 and women aged 18–54. The calculation of the incidence and prevalence rate was made per 100,000 population.

Results. The average annual values of the incidence and prevalence of male infertility in Russia were 34,0 ⁰/₀₀₀₀ and 94,0 ⁰/₀₀₀₀. For female infertility, the values were 204,1 ⁰/₀₀₀₀ and 657,0 ⁰/₀₀₀₀, which exceeded the incidence and prevalence of male infertility by 6,0 and 7,0 times, respectively. However, literature data suggests that male and female factors have an equal impact on infertility in couples. Among the Federal Districts, the highest average annual incidence and prevalence of male infertility were found in the Urals (94,4 ⁰/₀₀₀₀ and 217,5 ⁰/₀₀₀₀) and the North Caucasus (68,5 ⁰/₀₀₀₀ and 254,5 ⁰/₀₀₀₀) federal districts, the lowest in the South (14,0 ⁰/₀₀₀₀ and 41,0 ⁰/₀₀₀₀) and the Far East federal districts (13,9 ⁰/₀₀₀₀ and 43,2 ⁰/₀₀₀₀). The highest rates of female infertility were also recorded in the Ural Federal District (297,0 ⁰/₀₀₀₀ and 924,2 ⁰/₀₀₀₀) and the North Caucasus Federal District (283,3 ⁰/₀₀₀₀ and 1146,3 ⁰/₀₀₀₀), while the lowest rates were recorded in the Southern Federal District (155,6 ⁰/₀₀₀₀ and 433,5 ⁰/₀₀₀₀) and the Central Federal District.

Conclusions. The identified regional features indicate the need to improve approaches to comprehensive prevention of male and female infertility, taking into account demographic factors in different territories. Interdisciplinary cooperation as part of systematic efforts to reduce the burden of infertility should be a priority in the organization of reproductive care for the population.

Relevance. The article describes the practical experience of participating in the independent monitoring of the fifth round of supplementary immunization against poliomyelitis in October 2010 in the Republic of Tajikistan, where the largest outbreak in the WHO European Region occurred, caused by an imported wild poliovirus type 1 from India.

Aim. To summarize the experience of independent monitoring for assessing vaccination coverage, identifying unvaccinated children, and optimizing safety measures in the field.

Materials and Methods. The experience of active identification of unvaccinated children in organized groups, at markets, on the streets, in private households, and among the nomadic population using the method of fingernail marking with a black marker is described. The forms of independent assessment of the immunization campaign are presented.

Results. An analysis of coverage was conducted, and the reasons for non-vaccination were identified. Over four days of work in this region, we actively interviewed 302 children. In 31 children, there was no vaccination mark; 20 children were unvaccinated. Children who had no vaccination mark were vaccinated on the spot. Also, issues of ensuring the safety of the epidemiologist in the field when traveling to regions with an elevated level of danger were considered.

Conclusion. The marking method allows for objective assessment of coverage and avoids the use of paper documentation among the nomadic population. A timely responsive vaccination campaign can contain a large-scale outbreak, but the ultimate global eradication of poliomyelitis requires the resolution of political and social issues.

Relevance. Secondary spread of pertussis in schools is driven by waning immunity by the age of 6–7 years, low clinical vigilance among healthcare workers regarding pertussis in over 5 years old, and close contact within organized groups. The scope and quality of anti-epidemic measures play a key role in the rapid containment of infection outbreaks.

Aims. To evaluate the effectiveness of anti-epidemic measures in cluster outbreaks of pertussis in schools across several regions of the Russian Federation.

Materials and Methods. Data from 36 geographically and temporally unlinked cluster outbreaks of pertussis across 9 regions of the Russian Federation in 2023 (the period of the highest incidence peak in 26 years) were analyzed. Standard reporting forms and custom-developed evaluation tables were utilized, capturing parameters such as outbreak duration, number of cases and contacts, laboratory testing coverage, and the timing and scope of implemented interventions (including the transition to remote learning).

Results. The mean duration of outbreak monitoring was 41 days (range: 21 to 88 days). In all outbreaks, anti-epidemic measures (isolation, medical surveillance, and room ventilation) were implemented promptly. The transition to remote learning was implemented in 14 outbreaks. A positive correlation was found between the number of cases and both the number of classes switched to remote learning (rs = 0.63, p < 0.001) and the timing of this transition (rs = 0.53, p = 0.001). This indicates that remote learning was resorted to out of necessity in large, prolonged outbreaks, when standard containment measures had already failed to yield results.

Conclusions. The prolonged duration and scale of outbreaks indicate a lack of immune protection among schoolchildren. Transitioning to remote learning is effective as an anti-epidemic measure only during the early stages of an outbreak. Monitoring and validation of clear criteria for evaluating the effectiveness of anti-epidemic measures in pertussis outbreaks are required. Medical surveillance and laboratory testing of exposed individuals are critical for the early detection of cases and their prompt removal from the school setting.

Relevance. The incidence of enterovirus infections (EVI) in the Russian Federation increases in the summer-autumn period, with outbreaks occurring. The highest incidence rates recorded in the Ural and Far Eastern Federal Districts. Aim. To study the manifestations of the EVI epidemic process in the Far Eastern Federal District in 2006–2024.

Materials and Methods. A retrospective epidemiological analysis of EVI incidence in the subjects of the Far Eastern Federal District conducted using nonparametric and parametric statistical methods.

Results. In the Far Eastern Federal District a trend toward a moderate increase in EVI incidence with an increase in the registration of outbreaks has been identified. Most cases of infection occur in children aged 0 to 6 years, with children aged 1–2 years and up to one year being at risk. Increases in the incidence of enterovirus infections are largely associated with the circulation of certain enterovirus genotypes, with Enterovirus alphacoxsackie species predominating in the etiologic structure since 2017. A downward trend in the incidence of enteroviral meningitis has been observed. Among the clinical manifestations of enterovirus infections, the incidence of herpangina and exanthemic forms has increased.

Conclusions. The dominance of E. alphacoxsackie species could has lead to a change in the clinical patterns of enterovirus infections and, likely, the age distribution of affected children, as well as an increase in outbreaks. Multiple transmission routes, high contagiousness, and prolonged shedding of E. alphacoxsackie species require anti-epidemic measures not only during the seasonal but also during the interepidemic period.

Relevance. Globally disseminated genetic lineages of Klebsiella pneumoniae characterized by the presence and rapid acquisition of multiple antimicrobial resistance determinants and virulence factors are known as epidemic clones or clonal groups of high risk. At present, sequence type ST395 represents the predominant epidemic clone of K. pneumoniae circulating in the Russian Federation.

Aims. To investigate the genetic diversity of K. pneumoniae strains isolated in hospitals from different regions of the Russian Federation using whole-genome sequencing data, with particular emphasis on the dominant epidemic clone ST395.

Materials and Methods. Whole-genome sequencing data from 162 clinical K. pneumoniae isolates collected in six medical institutions located in Moscow, Barnaul, and Orenburg were analyzed.

Results. Among the 162 isolates examined, the most prevalent genetic lineage was ST395 (62/162; 38 %), which was detected in all participating hospitals. All analyzed K. pneumoniae isolates harbored a broad repertoire of genomic resistance determinants to at least nine classes of antibacterial agents, including aminoglycosides, beta-lactams (including carbapenems), phenicols, trimethoprim, fosfomycin, macrolides, fluoroquinolones, sulfonamides, and tetracyclines. A substantial proportion of ST395 isolates (77.7 %, 49/63) carried combinations of three or more distinct betalactamase genes, and the most interesting fact was the co-occurrence of blaNDM with blaCTX and blaTEM. Phylogenetic analysis demonstrated the formation of several clusters comprising isolates from different medical institutions. Isolates from one hospital in Moscow and one isolate from Barnaul were assigned to the same epidemic clone.

Conclusion. Genomically closely related, and in some cases apparently identical, strains were identified in geographically distant medical institutions. These findings underscore the importance of assigning isolates to epidemic clones, as such classification enables a more accurate assessment of their epidemic potential.