Vol 13, No 4 (2023)

Natural killer (NK) cells represent one of the innate lymphoid cell subsets, which are often studied in the context of antitumor and antiviral immunity, as well as due to their localization in the zone of the mother-fetus contact (in the uterus), therefore underlying their extensive investigation in developing pregnancy. At the same time, their role in antibacterial immune response has been poorly examined. Because NK cells can produce cytokines, one of putative options for their participation in eliminating prokaryotic pathogens may be coupled to regulation of immune system cells such as dendritic cells, macrophages, etc. However, there have been also described variants of contact cytolysis of cells infected with intracellular bacteria enabled due to cytotoxic proteins — perforin, granzymes, granulisin found in NK cells. In recent years, it has become known that NK cells take part in development of immune response against extracellular bacteria including the ESKAPE group bacteria, which includes opportunistic prokaryotes that most actively develop antibiotic resistance and cause nosocomial infections. Here, we attempted to review the data on the role NK cells play in antibacterial immunity. Assessing a crosstalk between ESKAPE group bacteria and NK cells also attracts researchers due to the ability of prokaryotes to alter functions of immune cells, but very little is known about the effects they exert on NK cells. At the same time, such data could be applied to seek out for new ways to treat oncological diseases as well as pave the basis for new approaches to regulating NK cell characteristics in reproductive pathologies. As mentioned earlier, the latter occur in the decidual membrane, where they can interact with fetal cells including trophoblast cells. It is believed that cells can mutually regulate each other’s properties necessary for the course of physiological pregnancy. Probably, imbalance in this system can lead to development of reproductive pathologies. The review summarizes the currently available data on the effects of ESKAPE group bacteria on NK cells, and also considers putative mechanisms for emergence of impaired interaction between NK cells and trophoblasts exposed to ESKAPE group bacteria. Owing to few publications available on this phenomenon, the experimental study assessing an impact of ESKAPE group bacteria on NK cell properties is envisioned as a necessary stage in development of contemporary biology.

A proper and representative monitoring of SARS-CoV-2 herd immunity including a long-term health impact on recovered patients and vaccinated individuals is of great importance. For this, a monitoring campaign should assesses both humoral and T-cell immune arms. Upon that, analyzing antigen specific-cell activation and cellular phenotype are informative. We developed a flow cytometry method for detection of intracellular IFNγ-producing antigen-reactive T cells after exposure of human peripheral blood mononuclear cells (PBMC) to SARS-CoV-2 virus antigens. The method was validated according to the following characteristics: sensitivity, specificity, precision, and robustness. We used positive samples from donors recovered from COVID-19 and negative samples from donors who had no contact with COVID-19 patients and lacking antibodies to SARS-CoV-2. All samples were tested by laboratory methods. Peripheral blood mononuclear cells were isolated from donor blood by centrifugation in a Ficoll density gradient. Specific T cells were stimulated with S-protein as well as N, M, ORF3a, and ORF7a protein peptides to count IFNγ-producing T cells by flow cytometer. The data were statistically analyzed. The area limited by ROC-curve and false positive rate (AUC) for CD4 and CD8 cells was from 0.97 to 1.00. Precision was considered acceptable because the coefficient of variation for all PBCM did not exceed 20%. Robustness was confirmed for frozen and freshly prepared PBMC samples. The thresholds levels to recognize immune and non-immune samples were defined for CD4-positive T-cells (0.029%) and CD8-positive T-cells (0.064–0.068%). Also, acceptance criteria for positive and negative controls were defined. Based on the validation, the suitability of the method “Evaluation of antigen-reactive T cells that produce intracellular IFN in response to SARS-CoV-2 virus antigens by flow cytometry” was confirmed. The method allows for reliable data that was used to characterize standard control samples for internal quality control of TigraTest® SARS-CoV-2 kits.

Background. The course of the COVID-19 epidemic process depends on population immunity which prevents pathogen spread. Aim: to study an evolution of SARS-CoV-2 humoral immunity in the Belarusian population rela- tive to COVID-19 pandemic dynamics.

Materials and methods. The work was carried out according to a methodology for assessing herd immunity developed by Rospotrebnadzor (Russia) and the Belarusian Ministry of Health involving the St. Petersburg Pasteur Institute (SPPI) by taking into account the WHO recommendations. The study was approved by the Bioethics Committee of Belarus and the SPPI Bioethics Committee. Participant selection was carried out by ques- tionnaire using a cloud (internet server) service. To monitor herd immunity, a cohort of 4661 subjects (involved at all stages of seromonitoring) was formed from the total volunteer group. Study subjects were randomized into groups based on age (1–17, 18–29, 30–39, 40–49, 50–59, 60–69, 70+ years), geographic region, and occupation. For the detection of antibodies (Abs) against SARS-CoV-2 nucleocapsid (Nc) and S glycoprotein receptor-binding domain (RBD), rel- evant assay systems were used according to the manufacturer’s instructions. A four-stage study was conducted according to a unified scheme.

Results. At stage 1 (pandemic month 15), herd immunity was mainly accounted for by Nc+RBD+ Ab status alone. By stage 2 (4 months later), its specific proportion decreased by 1.2-fold, whereas percentage of subjects solely bearing RBD-specific Abs increased by 1.7-fold. At stages 3 and 4 (9 and 19 months after the onset) vs. stage 2, percent- age of subjects with RBD+Nc– decreased by 3.5%; the proportion of persons with Nc+RBD– Abs increased by 1.5-fold.

The most important contributor in herd immunity turned out to be due to population vaccination, with coverage reaching 70% by stage 4. Among vaccines, compared with whole-virion, inactivated BIBP-CorV vaccine the Sputnik V and Sputnik Light vector were used most often.

Conclusion. The evolution of herd SARS-CoV-2 humoral immunity included a series of changes in circulating Ab levels (Nc, RBD). The hybrid immunity formed helped to reduce the incidence of COVID-19 to sporadic level.

Measles is a highly contagious, vaccine-preventable anthroponotic infection. Despite the policy of active measles vaccination for entire global population, measles has not completely disappeared, it wanes and waxes in outbreaks. It has been shown that not only the unvaccinated but also the vaccinated, which is quite understandable, subjects are involved in measles progression. The study was aimed at assessing features of the immune response in adult measles patients at rise in disease incidence upon its eradication. 1.158 blood sera from measles patients aged 18 to 70 living in Moscow and the Moscow region were studied by ELISA (Euroimmun, Germany). The vast majority of subjects were aged 18–40 years comprising 72.36% cases. 69 sera collected at a later timepoint (10–20 days from rash onset) were excluded and analyzed separately. According to anti-measles IgG and avidity level, the data were stratified as follows: group 1 with a primary type of immune response — 582 sera (53.44%), not vaccinated in childhood; group 2 (secondary response) — 446 sera (40.96%), vaccinated in childhood, but lost anti-measles antibodies; group 3 with intermediate level of parameters — 61 sera. To clarify the type of immune response in group 3, an additional analysis of the spectrum of anti-measles antibody subclasses was carried out. It was shown that a mixed type of response was detected in this group: 31 subjects mainly had primary immune response, and 30 subjects — secondary immune response. At the same time, 40 out of 61 subjects were vaccinated against measles 1–3 months prior to disease onset, i.e., it was overlapped on arising post-vaccination immunity. Thus, the previously identified trend towards the loss of post-vaccination immunity among older schoolchildren and young adults vaccinated in childhood who are involved in the epidemic process continues to worsen.

Introduction. Clinical evidence suggests that certain probiotics may help treat and prevent viral infections. To date, the effectiveness of probiotics in the alleviation of COVID-19 has not been established. The aim of this systematic review was to assess the role of probiotics in the prevention and treatment of COVID-19.

Materials and methods. An extensive search of four electronic databases was performed which included Embase, Scopus, Web of Science, and PubMed from November 2019 to June 2022. After reviewing the references list of related articles additional studies were identified. A multiple combination of keywords validated by MESH were used to search the databases. Study selection was performed according to an inclusion and exclusion criteria.

Results. Twenty-three articles met the study inclusion criteria. Six articles were conducted in vitro while the remaining studies were conducted in the human population (in vivo). The type of probiotic was defined in eighteen studies. There were two studies that used supplements (vitamins, herbals, minerals, etc.) in addition to probiotics. The largest sample size was 445 850 participants which were from a study that used an application-based survey. The majority of studies found that probiotics had a positive effect on the COVID-19 disease. The benefits included early remission of COVID-19 symptoms and a shorter duration of sickness (10 studies), lower mortality rates (3 studies), and decreased hospitalization and length of stay (3 studies). Six in vitro studies found that probiotics were beneficial against SARS-CoV-2 through antiviral effects. There were only two studies that found probiotics to be ineffective or caused negative effects when consumed in COVID-19 patients.

Conclusion. Available evidence supports the antiviral role of probiotics on prevention and treatment of COVID-19. The antiviral potential of Lactobacillus paracasei metabolite PlnE and PlnF against SARS-CoV-2 may explain the effectiveness of probiotics on COVID-19.

The aim of the study was to evaluate the data of phylogenetically analyzed nucleotide sequences from the K. pneumoniae strain uge genes carried out in the perinatal center. Materials and methods. Fifty-six sequences of the K. pneumoniae uge gene were analyzed. The uge gene was detected by real-time PCR using DT light amplifier (Russia). Results. The rate of K. pneumoniae strains among patients of obstetric and gynecological departments in 2020–2023 averaged 1.4%. In pediatric hospitals, the isolation of K. pneumoniae strains comprised 12–14% in 2020, 2021 and 2023. In 2022, a fourfold decrease in detected K. pneumoniae strains was recorded. Phylogenetic analysis showed that the nucleotide sequences were significantly grouped into 14 clusters. The K. pneumoniae virulence factor uge gene is found in 64.3% cases. The nucleotide sequences allowed to detect heterogeneous K. pneumoniae strain population isolated from patients at the perinatal center from 2019 to 2023 analyzed by the phylogenetic method. There are clusters that combine K. pneumoniae genovariants isolated in 2019 and not replenished with new isolates, which confirms the effectiveness of ongoing anti-epidemic measures, enhanced during COVID-19 spread, excluding the transmission of an infectious agent from a source to a susceptible organism in nosocomial environment. P249Q, N279L amino acid substitutions within the uge gene were determined, which distinguish hypervirulent strains from those with a lower degree of pathogenicity. Out of five mother-child pairs, in four — nucleotide sequences of K. pneumoniae strain uge gene were genetically closer to each other than to other strains isolated from patients of the Medical Departments suggesting about a high degree of their relationship, highly likely indicating that the source of the strain for the child was the paired mother, and not the patients of the departments or the staff of the institution. In one mother-child pair, K. pneumoniae strains belonged to different clusters. The isolate obtained on 09/06/2021 from neonatal faeces (age: 7 days old) was grouped with strains isolated on 12/12/2020 from a patient in the maternity ward and in Laos in 2013 (CP035196). K. pneumoniae isolated on 06/04/2021 from the urine of a woman, was significantly grouped with strains included in cluster 13. Conclusion. An opportunity for improving local microbiological monitoring by sequencing and phylogenetic analysis of K. pneumoniae uge gene has been demonstrated. Assessment of changes in the intraspecies population pattern of HCAI pathogens is necessary for a timely and reasonable response to the deterioration of the epidemiological situation.

Introduction. Despite the substantial progress in intensive cares, sepsis is still an important cause of neonatal mortality. Given the role of vitamin D in infection control, this study was conducted to compare vitamin D level in infected and uninfected preterm infants. Materials and methods. This cross-sectional study was carried out on 87 preterm infants (45 infected infants and 42 uninfected infants) hospitalized in Mashhad Ghaem Hospital, Iran, during 2015–2017. The subjects were selected by using convenience sampling. The infected infants (n = 45) included babies with clinical and laboratory findings compatible with infection and/or positive blood or cerebrospinal fluid cultures. The serum levels vitamin D were measured in all infants. A researcher-made questionnaire containing demographic, clinical and laboratory features of infants was used. In addition, independent t-test and chi-square test were applied. SPSS was used to perform the statistical data analysis. Results. 83% of infants had vitamin D deficiency 34.5%, 26.4%, and 21.8% of whom exhibited severe (less than 10 ng/ml), moderate (10.1–20 ng/ml), mild deficiency (20.1–30 ng/ml), respectively. The mean vitamin D level of infants was 23.31±9.40 ng/ml in the control group and 11.02±8.64 ng/ml in the case group (p = 0.000). In the case group, the mean vitamin D was 8.14±5.53 ng/ml in early sepsis and 12.62±9.75 ng/ml in late-onset sepsis (p = 0.121). 95% of infected infants and 71% of uninfected infants had vitamin D less than 30 ng/ml (p = 0.003). Conclusion. Vitamin D deficiency is very common in preterm infants. Serum vitamin D levels in infants with sepsis were lower than those in uninfected infants. Therefore, the correction of vitamin D deficiency may contribute to better control of neonatal infection.

The incidence of cervical cancer (CC) in Russia remains at a high level and ranks fourth among all cancers. CC is preceded by mild, moderate, and severe cervical intraepithelial neoplasia. Human papillomavirus (HPV) is known to be the main cause for its development being responsible for 99% cancer cases. Despite HPV infection, the oncological process occurs only under certain conditions. There are risk factors that indirectly affect the course and emergence of cervical dysplasia. In recent years, the role of cervico-vaginal microbiome for onset and progression of this pathology has been actively discussed. Many studies evidence that dysbiosis along with cervical intraepithelial dysplasia is associated with increased HPV viral load, additionally allowing to clarify a role of specific microorganisms. Despite the knowledge rapidly accumulating about the nature of vaginal microbiome in cervical precancerous processes, the level of its impact on disease course has not been fully investigated and is of great interest. Identification of microorganisms that affect emergence and progression of this pathology will allow to prevent and apply select approach to treatment of dysbiosis. The aim of our study was to identify a relation between cervical tissue and luminal culturome and severe cervical intraepithelial neoplasia. The study evaluated the microbiota of cervical and cervical canal mucosa biopsy in patients with cervical intraepithelial changes. According to the study results, the Streptococcus genus representatives were significantly more frequent in cervical biopsy specimens in severe dysplasia vs. no cervical intraepithelial changes, whereas cervical canal cultures provided comparable data. Bacteria from the Corynebacterium genus were found in cervical biopsy specimens 3 times more often than in smear from the cervical canal mucous membrane. The microbiota from cervical and cervical canal biopsy specimens differ qualitatively and quantitatively particularly regarding prevalence of Streptococcus spp. representatives being more common in patients with cervical dysplasia. Corynebacterium spp. were detected more often in cervical biopsy specimens than in cervical canal smears. Thus, the method of collecting biological material has a great influence on final results.

The paper is prepared for the 100th anniversary of the Department of Microbiology at the Military Medical Academy and the 100th anniversary of naming Louis Pasteur Saint Petersburg Research Institute of Epidemiology and Microbiology. The article is devoted to the history of interaction between Kazan and Saint Petersburg (Leningrad) microbiological schools — from early XXth century to the present day. It provides historical milestones in developing Departments of Microbiology at the Kazan State Medical University and the Military Medical Academy as well as research departments both in the Kazan Research Institute of Epidemiology and Microbiology and the Saint Petersburg Research Institute of Epidemiology and Microbiology, highlights aspects of the joint establishment and development of the Kazan and Saint Petersburg Microbiology Schools, provides brief biographical data of the microbiology department staff members, whose activities were related to work in such institutions. Biographical information, personal characteristics, major directions in scientific and practical activities of famous microbiologists who worked in various periods of own lives in Saint Petersburg (Leningrad) and Kazan (V.M. Aristovsky, R.R. Geltzer, P.N. Kashkin, I.I. Pryakhin, A.R. Konova, A.G. Grigorieva-Berenstein) are presented. The efforts of Leningrad and Kazan scientists during the Great Patriotic War scientists to jointly develop and improve methods of industrial manufacture of antibiotics, therapeutic and prophylactic sera, bacteriophages are covered in detail. The article was prepared using primary sources: publications, memoirs of employees of the Department of Microbiology at the KSMU, VMA, KNIEM, Saint Petersburg Pasteur Institute, documents from the archives of personnel departments, as well as the National Archive of the Republic of Tatarstan, archival materials of the Departments of Microbiology of KSMU and VMA. The main scientific achievements of representatives of the Kazan and Saint Petersburg Microbiology Schools, their scientific contribution to development of microbiology field are described. Finally, it is noted about a need to preserve historical memory about the contribution of Russian scientists to development of microbiology field.

The organization of the North-Western District Center for AIDS Prevention and Control (AIDS Center) originates from the onset of the HIV epidemic in the Russian Federation. Over the 35 years of work, the staff of the AIDS Center has made an invaluable contribution to the development of HIV diagnostics, the introduction of new clinical and preventive technologies, patient counseling, and training of qualified personnel. The anniversary article highlights the main stages regarding establishment of the AIDS Center as a structural unit of the Saint Petersburg Pasteur Research Institute. The versatile naturally multidisciplinary functions and tasks related to the AIDS Center organization, its major Russia-wide and global achievements are considered. Special attention is paid to the long-term international cooperation, the results of diverse implemented programs and projects supported by the World Health Organization (WHO) as well as the Joint United Nations Programme on HIV/AIDS. The AIDS Center continues to cooperate with the main scientific facilities such as the Pavlov First Saint Petersburg State Medical University, Institute of Experimental Medicine, N.P. Bekhtereva Institute of the Human Brain of the Russian Academy of Sciences, etc. The ongoing joint research invariably contributes to assessing the epidemiology and clinical course of various viral infections and comorbid conditions. The knowledge acquired becomes regularly summarized and published in a series of monographs, journal articles being presented demonstrated at conferences of various levels. Currently, the AIDS Center is represented by several structural divisions continuing to conduct practical and scientific activities on investigating HIV and viral hepatitis.