Vol 101, No 1 (2024)

Introduction. The COVID-19 pandemic, etiologically related to SARS-CoV-2, was the longest-lasting pandemic for an acute respiratory disease and had a significant impact on demography, economics and politics globally. Experiences with this pandemic are significant for the sustainable development of human society. A detailed analysis of these experiences in epidemic control should include details of the pathogen evolution down to the regional level.

The aim of the study was to establish the regularities of the COVID-19 epidemic process in connection with the change of the pathogen genetic variants on the territory of Primorsky Krai.

Materials and methods. A retrospective epidemiological analysis of COVID-19 incidence and dynamics of circulation of SARS-CoV-2 genetic variants during the pandemic of this disease (11.03.2020–05.05.2023) in Primorsky Krai was carried out. Data was gathered from the Department of Rospotrebnadzor in Primorsky Krai, the Centre of Hygiene and Epidemiology in Primorsky Krai, as well as the G.P. Somov Research Institute of Epidemiology and Microbiology of the Russian Federation and Russian Platform for Aggregation of Information on Virus Genomes (VGARus). In particular, 1055 nucleotide sequences of full-length SARS-CoV-2 genomes from Primorsky Krai, among which 553 were sequenced at the G.P. Somov Research Institute of Epidemiology and Microbiology were included in analysis.

Results. When analyzing the epidemic dynamics of COVID-19 in Primorsky Krai (2020–2023), 7 rises in incidence with different clinical and epidemiological symptoms depending on the genetic variants of the pathogen were identified. At the beginning of the pandemic in Primorsky Krai, as well as throughout Russia, Wuhan-like variants of SARS-CoV-2 were predominant, though later, Delta and Omicron genetic variants were in the majority. By the end of April — beginning of May 2023, the proportion of Omicron sub-variants (XBB.1.9.2 and XBB.1.16) in Primorsky Krai was higher than the Russian average and comparable to that in neighboring countries (Republic of Korea and Japan).

Conclusion. Due to the ongoing evolution of SARS-CoV-2, the possibility of the emergence of new pathogens, the peculiarities of the geographical location as well as political and economic importance of Primorsky Krai, it is necessary to consistently improve regional capabilities for operational molecular virological monitoring.

Introduction. For early immunodiagnostics of tuberculosis (TB) in Russia, the Mantoux test (MT) has been used for decades; since 2013, the recombinant tuberculosis antigen (RTA) test has seen widespread use.

The objective of this retrospective analytic observational cohort study was to evaluate the results of immunodiagnostics for TB in children with newly diagnosed active TB.

Materials and methods. We studied data from Russian TB institutions on the results of MT and RTA assay in children with active and inactive TB first detected in 2013–2018, as well as children with active TB first detected in Moscow in 2017–2022.

Results and discussion. In 2013–2018, out of 12,902 examined children with active TB, 11,673 (90.5%) had positive results of both skin tests and 198 (1.5%) had negative results. A negative RTA assay result with positive MT was found in 861 (6.7%) patients, and a positive RTA assay result with negative MT in 170 (1.3%). The sensitivity of the RTA assay in detecting active TB was 91.3%, while the sensitivity of MT was 97.2% (p < 0.01). Similar data were obtained in the same regions in 14,127 children with inactive TB: the sensitivity of MT was higher than that of the RTA assay — 97.2% versus 95.2% (p < 0.01). In Moscow, due to the small number of observations in 2022, it was not possible to show statistical reliability of the difference between the sensitivity of MT and RTA assay in detecting active TB in 2017–2022 (95.8% and 92.1% respectively; p > 0.5). For the results obtained in 2017–2021, the difference was significant (p < 0.05).

Conclusion. The sensitivity of MT is higher than that of the RTA assay in screening children for TB. It is recommended to use the more sensitive MT test for screening children; screening with the RTA assay will increase the number of undetected and undiagnosed cases of active TB in children. Currently, MT cannot be excluded from the algorithm of early TB diagnosis in children.

Introduction. Uropathogenic Escherichia coli (UPEC) are characterized by the ability to survive and reproduce in the urinary tract due to the presence of specific virulence factors. In routine laboratory practice, the detection of diagnostically significant bacteriuria does not provide an idea of the level of infection of the urinary system (renal parenchyma, bladder), the pathogenic potential of the strain in the progression and chronicity of the infectious process, and the occurrence of life-threatening conditions (urosepsis, meningitis).

Objective. To characterize the population structure, genetic diversity and pathogenic potential of E. coli strains isolated from urine.

Materials and methods. 194 strains of E. coli isolated from urine were studied. Detection of 17 genes encoding the synthesis of: adhesins (pap, fimH, sfa, focG, afa), toxins (hlyA, cvaC, cnf, cdtB), capsular antigens (kpsMTII, kpsMTIII, kpsMT K1), siderophores (fyuA, iutA), invasins (ibeA), genetic markers of the pathogenicity island (PAI) of UPEC CFT073, the gene (traT) encoding serum resistance capacity and phylogenetic groups were performed by PCR (CXT-1000, BioRad, USA) with published primers (Synthol, Sibenzyme, Evrogen, Russia). To assess the statistical significance of differences, Fisher's exact test was used. Differences were considered significant at a confidence interval of 95% (p < 0.05).

Results. E. coli strains more often (p < 0.05) belonged to the phylogenetic group B2 (57.7%). Pathogenetically significant virulence determinants were identified in 97.9% of strains. Based on the combination of 17 genes, 134 individual virulence genotypes were identified. In 93.3% of strains, a genetic predisposition to the occurrence of recurrent urinary tract infections (UTIs) was revealed, in 6.9% there was a potential for the development of pyelonephritis and recurrent cystitis. Markers of life-threatening complications of UTI were identified in 12% of strains, of which 10.7% were the development of urosepsis and 1.3% were meningitis.

Conclusion. Detection of a complex of genes in E. coli strains isolated from urine confirms the etiological significance of the isolate and allows one to assess the pathogenic potential for the development of chronic and severe life-threatening complications.

Objective: to investigate the regional peculiarities of Streptococcus pneumoniae carriage in the pediatric population and characterize the dominant serotypes of the pathogen.

Materials and methods. The clinical study group consisted of 509 healthy children attending preschool institutions. Examination of nasopharyngeal samples for the detection of S. pneumonae was carried out by classical bacteriological and molecular biological methods. The serotype was determined by real-time PCR. Genome-wide sequencing of the serogroups 15 and 11 isolates and bioinformatic analysis were performed.

Results. The S. pneumoniae bacterial carriers in the group of healthy children was detected in 207 children (40.7%), while the frequency of detection of S. pneumoniae in urban children living in Kazan was significantly higher than in children living in rural area and amounted to 53.4 and 31.1%, respectively (p < 0.05). Among children vaccinated with the 13-valent pneumococcal conjugate vaccine (PCV-13), S. pneumoniae carriers were not detected in 57.5% of cases. There were no significant differences in the degree of nasopharyngeal contamination depending on the vaccination status. Analysis of the serotype composition indicates the predominance of vaccine serotypes (57.7%), while the share of serotypes included in the PСV-13 vaccine accounts for only 24.7%, the share of non-vaccine serotypes was 32.1%, untyped — 10.2%. In unvaccinated children, vaccine serotypes that are part of the PCV-13 and 23-valent polysaccharide pneumococcal vaccine prevailed (PPSV-23): 6ABCD (21%), 11 AD (15%), 14 (13%). In vaccinated children, serotypes not included in the active vaccines dominated: 15AF (17.4%), 23A (19.2%), as well as 11AD (19.6%) (11А is included in PPSV-23). The 27 Kz isolate (serotype 15C) belonged to one of the most common sequence types ST1025. The 105_Kz isolate (serotype 11D) belonged to another common sequence type ST 62.

Conclusion. In order to improve epidemiological surveillance of pneumococcal infection, it is necessary to introduce the monitoring of circulating clonal complexes of dominant S. pneumoniae serogroups and analyze the genetic determinants of antibiotic resistance and virulence depending on the sequence type.

Introduction. The relevance of the study is due to the need to assess the real expansion of West Nile fever (WNF) in Russia, analyze the manifestations of epizootic and epidemic processes and study the population structure of West Nile virus (WNV).

Aim. To obtain objective data on the intensity of WNV circulation in certain territories of Russia and study the properties of the isolated strains of the pathogen.

Materials and methods. 4564 samples of field material from 23 subjects of the Russian Federation and 1547 samples of clinical material from 12 subjects of the Russian Federation were examined. A set of laboratory diagnostic methods was used: ELISA, RT-PCR, virological, sequencing.

Results. In 20 out of 1331 (1.5%) examined febrile patients, IgM antibodies to WNV were detected, including positive cases identified for the first time in the Karachay-Cherkess Republic, Tver and Vladimir regions. The presence of immunity to WNV was found on average in 8.6% of 11 federal subjects' population with high seroprevalence rates in Zaporozhye (24,5%), Tula (15,4%) and Kursk (11,1%) regions. Low-avidity IgG antibodies were detected in 44 (33,1%) samples from a population of 9 federal subjects. Intensive circulation of WNV lineage 2 in the epizootic cycle in the southern part of European Russia was confirmed. 12 WNV isolates were obtained, including those isolated for the first time in the Republic of Crimea, the Karachay-Cherkess Republic and the Stavropol Territory. The heterogeneity of circulating WNF causative agent's strains related to the two clades of the WNV lineage 2 formed in 2021 and 2022 was established.

Conclusion. In the course of comprehensive monitoring studies, a new northern border of the WNF range was established, which as of 2022 passes through the territory of the Tver region. Data from seroepidemiological studies, including the detection of low-avidity IgG antibodies, confirm fairly intense, but undiagnosed contact of the population of the European part of Russia with the WNF pathogen. In the southern region of the European part of Russia, WNV genotype 2 predominantly circulates, belonging to at least two clades formed in 2021 and 2022.

Introduction. It is established that the severity of SARS-CoV-2 infections varies between individuals without underlying health conditions and those with chronic illnesses like asthma.

Aim: to assess the gene expression of COVID-19 patients with and without asthma.

Materials and Methods. 20 patient profiles out of a total of 288 were selected from Gene Expression Omnibus (GSE178399). All patients have positive PCR tests and were divided into 4 groups. GEO2R was used to estimate the comparison between groups. STRING tool was used to measure the correlation between genes. The phylogenetic tree was extracted using iTOL. The heat map was extracted using iDEP.96.

Results. MMP10 (Matrix metalloproteinase-10), TNFRSF11B (Tumor necrosis factor receptor superfamily member 11B), CCL23 (C-C motif chemokine ligand 23), CD274 (Programmed cell death 1) CX3CL1 (C-X3-C motif chemokine), and IL17C (Interleukin-17C) had down-regulation for all patients. Transcriptome data conducted no correlation between the expression of MMP10 and asthma, although there is a significant correlation between the expression of MMP1 and sensitivity. The expression of IL17A, which is strongly related to allergic asthma, is decreased in non-asthmatic individuals but elevated in asthmatic patients, notably in survivors. Patients who were not asthmatic had significantly higher CXCL9 levels.

Conclusions. The study revealed a disparity in the relationship between imbalanced gene expressions in the groups examined. The gene expression of asthma patients who survived and died was not significantly different.

The aim of the review is to give a brief characteristic of cell cultures obtained from mammalian tissues and to consider the current possibilities and prospects for their use in virology.

The analysis of the literature data presented in the main databases, such as Web of Science, PubMed, Scopus, Elsevier, Google Scholar and RSCI (as of July 2023), indicates that various types of cell cultures are currently used in virological studies. The use of cell culture has a number of advantages over other in vitro and in vivo methods of virological research. The review provides numerous examples on the development of new methods of obtaining cell cultures for the cultivation of viruses. Among them are sensitive and reporter cell systems, the design of which can be a promising tool for diagnostics of existing and new unknown viral infections. Cell cultures are characterized as potential in vitro models in virology for developing new diagnostic test-systems and antiviral drugs. An important area of cell cultures application is their use as a substrate for the production of culture-derived vaccines. Another aspect of the cell cultures application is also highlighted, such as the study of the effect of the viruses on the host immune system or the mechanisms of immunopathogenesis of viral infections. It is concluded that the use of cell cultures remains currently and in the near future one of the most important methods in practical virology and in scientific research.