Russian Journal of Infection and Immunity

Introduction. Bacteria of the genus Aeromonas are widespread in the environment, including marine and freshwater ecosystems, therapeutic mud, and wastewater. In recent years, human diseases caused by Aeromonas spp. have been increasingly reported, especially in individuals with weakened immune system. Being resistant to multiple drugs, these bacteria isolated from water bodies, fish, and seafood on fish farms pose a potential threat to aquaculture production and their spread throughout the environment. This review on study results assessing biological properties of Aeromonas bacteria, systematizing data on the phenotypic and molecular genetic mechanisms of their pathogenicity, defines a strategy for an interdisciplinary approach to diagnose and prevent Aeromonas infection. The objective of this review is to summarize and analyze data on the biochemical and molecular genetic characteristics of Aeromonas bacteria and determine their clinical and sanitary-epidemiological significance. Materials and methods. Literature sources for this review were selected from the PubMed and Web of Science databases, and the eLIBRARY.ru scientific electronic library website. Initially, 98 scientific articles published between 2019 and 2025 were included in the work, covering the results from studies on the biological properties and prevalence of Aeromonas bacteria in patient biomaterials with bacterial infections, as well as their prevalence in environmental objects. The final version of the review included 65 references. Results. The scientific data presented here indicate a high frequency of detection of Aeromonas spp. in various environmental objects and those possessing pathogenicity factors. The presence of virulence and antimicrobial resistance determinants confirm their role in the development of human and animal as well as aquatic infections. Due to their ubiquitous distribution, metabolic and genetic characteristics, Aeromonas bacteria have been currently acquiring the status of a new pathogen and an indicator of resistance and virulence genes. Conclusion. The conducted analysis assessing results of studies on issues of identification, determination of phenotypic and genotypic characteristics, including antibiotic resistance underlying pathogenic potential of bacteria of the genus Aeromonas, suggests a need to further investigate these bacteria in the fields of healthcare, fish farming and agriculture.

Background. Human papillomavirus (HPV) is a well-established risk factor for oropharyngeal squamous cell carcinoma (OPSCC) and has also been implicated in oral squamous cell carcinoma (OSCC). However, global prevalence data for HPV in OSCC and OPSCC remain heterogeneous. This systematic review and meta-analysis aim to determine the pooled prevalence of HPV in OSCC and OPSCC, analyzing variations by gender, geographical distribution, and sample size. Materials and methods. A comprehensive search was conducted in PubMed for published literature till February 2025, identifying relevant studies reporting HPV prevalence in OSCC and OPSCC. A proportional meta-analysis was performed using a random-effects model with double arcsine transformation. Subgroup analyses were conducted based on gender, cancer type (OSCC vs OPSCC), and study location. Heterogeneity was assessed using the I² statistic, and publication bias was evaluated using funnel plots and Egger’s test. Results. A total of 103 studies, comprising 13 060 OSCC/OPSCC patients, were included. The pooled prevalence of HPV was significantly higher in OPSCC (45.95%) compared to OSCC (15.50%). South America exhibited the highest prevalence (38.58%), while regional differences were evident across other continents. Male patients showed a slightly higher HPV prevalence (24.36%) compared to females. Polymerase chain reaction and in situ hybridization were the most commonly used HPV detection methods. High heterogeneity (I² > 75%) was observed across studies, indicating methodological and population-based variability. Egger’s test did not show significant publication bias (p = 0.0931), though the funnel plot suggested some degree of asymmetry. Conclusion. This meta-analysis provides comprehensive global estimates of HPV prevalence in OSCC and OPSCC, reinforcing the strong association between HPV and OPSCC while highlighting its relatively lower prevalence in OSCC. Regional and gender-based differences underline the need for standardized HPV detection protocols and expanded vaccination programs targeting both genders. Future research should focus on improving diagnostic accuracy and understanding HPV’s role in OSCC pathogenesis.

Seasonal influenza A viruses including A(H1N1)pdm09 and A(H3N2) subtypes infect over 5–15% of the global population annually. According to epidemiological data, influenza A(H3N2) viruses are associated with more severe disease progression and the development of hemorrhagic syndrome as well as different thrombotic complications associated with activated vascular endothelial cells. The aim of the study was to investigate the effect of influenza A(H3N2) virus on the morphofunctional properties of blood vessel endothelium during the acute phase of infection. Materials and methods. Wistar rats were intranasally infected with influenza A virus A/Port Chalmers/1/1973 (H3N2) in a volume of 0.1 ml and subsequently euthanized at 1- and 4-days post infection (d.p.i.) (n = 5). Animals in control group were intranasally administered DMEM medium (0.1 ml). After necropsy, lung and mesentery tissues were collected to assess viral infectious activity titer. Additionally, severity of histopathological alterations in lung blood vessel endothelium and mesentery was assessed, the expression level of endothelial nitric oxide synthase (eNOS) in pulmonary and mesentery vascular endothelium was measured by immunohistochemical analysis, and the parameters of vasomotor activity in mesenteric arteries using wire myography was assessed. Results. Influenza A(H3N2) virus induced morphological changes in lung blood vessels on days 1 and 4, decreased eNOS expression levels in lung vessel endothelium at 1 d.p.i., and in mesenteric blood vessel endothelium at 1 and 4 d.p.i. Furthermore, the response of mesenteric blood vessels to median phenylephrine concentrations on day 4 vs day 1 d.p.i. was 87.13% higher (p < 0.05), while the vascular response to premaximal acetylcholine concentrations on day 4 was 26.15% lower (p < 0.05) compared to control. Conclusion. Influenza A virus subtype H3N2 impairs the morphofunctional properties of the blood vessel endothelium in rat lungs and the functional properties of the vascular endothelium in the mesentery during the acute phase of infection, suggesting activation of endothelial cells at both local and systemic levels.

The aim of the study was to conduct, analyze and compare the characteristics of the immune response in chronic opisthorchiasis in residents of the Tyumen region in comparison with healthy individuals. To identify the features of immune response in chronic opisthorchiasis, 648 patients underwent comprehensive immunological studies. For comparison, samples of 50 conditionally healthy donors were used. A wide range of immunological indicators was assessed in all subjects. The study of T-lymphocytes, T-helper cells, T-cytotoxic cells, NK cells, activated T-lymphocytes, and B-lymphocytes was performed by flow cytometry. The concentration of IgG, IgA, IgM, and IgE immunoglobulins was quantitated by the enzyme immunoassay. The phagocytic activity of neutrophils was assessed by the ability of cells to absorb latex particles. Neutrophil metabolic activity was determined by cytochemical reduction of nitrosine tetrazolium to diformazane, and the level of neutrophil myeloperoxidase was detected by spectrophotometric method. The concentration of circulating immune complexes was determined by the precipitation method. Results. In patients with chronic opisthorchiasis, a set of changes in the work of nonspecific and specific immunity was revealed. Activation of the neutrophilic arm was revealed, which is expressed by significantly increased myeloperoxidase concentration, neutrophil bactericidal and phagocytic abilities. A higher level of circulating immune complexes was found. Patients with Opisthorchis felineus invasion have a lower count of monocytes and NK cells. In the examined patients, an imbalance of major T-cell subpopulations was revealed: higher percentage of T-lymphocytes, which occurs due to elevated count number of helper populations, while in patients with chronic opisthorchiasis, the number of cytotoxic T-lymphocytes decreases and, subsequently, resulted in rise in immunoregulatory index. There is an increase in the number of cells responsible for the late activation and strength of the immune response from T-lymphocytes. An imbalance in the humoral arm of adaptive immunity has been revealed. With a simultaneous decrease in B-lymphocyte level, a high IgG content is observed. The study revealed a set of changes in the immune system in patients with chronic opisthorchiasis suggesting that patients with chronic opisthorchiasis are at higher risk of damage to their own tissues and organs, especially in case of elevated IgE and IgG levels.

M. tuberculosis-related mortality and morbidity remain one of the most relevant public health issues. Cell-mediated reactions involving both innate and adaptive cells play a major role protecting against M. tuberculosis. However, but it was noticed recently that diverse B cell subsets are also critical for controlling M. tuberculosis infection. Hence, our study was aimed to assess patterns for B cell subsets and circulating memory follicular Th (Tfh) cell subsets in patients with pulmonary tuberculosis (TB). Peripheral blood samples were collected from treatment naïve TB patients (TB, n = 37), and age- and gender-matched healthy controls (HC, n = 39). Lymphocytes were stained with fluorochrome-labeled antibodies to define B cell and Tfh cell subsets using multicolor flow cytometry. It was found that the percentage of IgD⁺CD27^–СD38^– “naïve” B cells was increased, whereas that of for IgD⁺CD27^–CD38⁺ activated “naive” and IgD⁺CD27^–CD38⁺⁺ circulating germinal-center B cell precursors decreased in TB patients vs control. The decreased relative and absolute frequencies of IgD⁺CD27⁺ unswitched memory B cells, as well as the decreased relative numbers of IgD^–CD27⁺ switched memory B cells were found in TB patients vs control. We revealed the increased relative and absolute numbers of CD24⁺⁺⁺CD38⁺⁺⁺ Breg cells in TB group vs control (7.83% (5.61; 15.14) vs 4.84% (2.38; 7.15), and 15 cell/1 μL (10; 26) vs 9 cell/1 μL (4; 17), р = 0.001 and р = 0.010, respectively). TB patients vs control had decreased relative and absolute frequencies of CXCR3⁺CCR6^– Tfh1 cells (27.86% (22.36; 32.04) vs 32.27% (26.02; 36.65), р = 0.009, and 26 cell/1 μL (14; 45) vs 37 cell/1 μL (26; 48), р = 0.011). Furthermore, the frequencies of circulating Tfh1 cells negatively correlated with the frequencies of IgD⁺CD27^–CD38⁺⁺ B cells (r = 0.425, р = 0.017) and CD24⁺⁺⁺CD38⁺⁺⁺ Bregs (r = 0.569, р = 0.001). Finally, we noticed that in patients with TB vs control subjects CXCR3^–CCR6^– Tfh2 level was increased (20.55% (15.84; 26.20) vs 16.86% (14.39; 22.05), р = 0.022), and correlated with the relative frequency of IgD⁺CD27^–CD38⁺ “naïve” В cells (r = 0.415, р = 0.020). Thus, the data obtained allow to presume that peripheral blood B cell and Tfh cell subset compositions in pulmonary TB patients are disturbed suggesting that humoral immune response may be altered not only locally (in the site of infection), but also at the level of peripheral lymphoid tissues.

Total arthroplasty is a key method for treating degenerative and dystrophic diseases of large joints. The most serious complication related to endoprosthesis is periprosthetic infection, the treatment of which involves significant economic costs and a high risk of recurrence. Therefore, during endoprosthetics, it is necessary to conduct a preliminary microbiological examination, which allows to choose the most effective etiotropic therapy especially important in case of antibiotic-resistant microorganisms, fungi and mixed infections. The aim of the study was to analyze the pattern of microorganisms isolated from synovial fluid in patients with chronic orthopedic infection of large joints of the extremities. The study included 79 patients with suspected periprosthetic infection and 15 patients with chronic arthritis combined with osteonecrosis. Synovial fluid samples were delivered to the microbiological laboratory of SamSMU Clinics, where positive samples were cultured and microorganisms were identified using MALDI-ToF mass spectrometry (Bruker, Germany). The study found that among Gram-positive pathogens, S. aureus was the most common — 45.9% (56 strains), S. epidermidis — 29.5% (36 strains) and C. striatum — 13.1% (16 strains) of cases. Among S. aureus, 17.9% were methicillin-resistant. K. pneumoniae was the dominant Gram-negative species (50%), E. coli was the second most common, with 33.2%. 9 strains of K. pneumoniae produced beta-lactamase, and carbapenemases were detected in 4 cases. All E. coli strains were producers of extended-spectrum beta-lactamases. In patients with chronic arthritis and osteonecrosis, Gram-positive pathogens were mainly isolated (73.3%), including methicillin-resistant S. aureus (25%). Gram-negative pathogens accounted for 26.7%, and extended-spectrum beta-lactamase producers prevailed. Hence, Gram-positive bacteria predominate in the pattern of pathogens, especially S. aureus and coagulase-negative Staphylococcus spp. Gram-negative microorganisms act as an etiological agent much less frequently, however, the frequency of prevalence for strains with multiple antibiotic resistance is increasing among them. Thus, conducting a preliminary microbiological examination to determine antibiotic sensitivity becomes a necessary step during endoprosthetics.

Introduction. Mass vaccination, implemented in Russia within the framework of the Russia National Vaccination Calendar, is a key component in the fight against vaccine-preventable infections (measles, mumps, rubella). The aim. The study’s aim was to assess herd immunity to the most common vaccine-preventable infections in several Russian regions. Materials and methods. The study involved 18 247 volunteers from several regions (Amur, Irkutsk, Nizhny Novgorod, Kaliningrad) and the Republic of Crimea. During the study, participants completed a questionnaire. A cohort of volunteers, stratified by age (1–5, 6–11, 12–17, 18–29, 30–39, 40–49, 50–59, 60–69, ≥ 70 years), was randomized using a web application. Antibodies to the measles, rubella, mumps were quantitated by ELISA (IgG) using Russian-made test systems. Results. The cohort average seropositivity magnitude for measles, mumps, and rubella were 75.7%, 84.0%, and 95.8%, respectively. For measles, the highest seropositivity level was observed in the group 1–11 years (Me = 74.8%; IQR = 68.5–83.5) and the group 60–70+ years (95.1%; IQR = = 93.2–95.8). Regarding mumps, these two ago groups also showed peak values: 1–11 years (Me = 85.9%; IQR = 81.4–92.5) and 60–70+ years (Me = 88.6%; IQR = 83.7–90.6). The lowest measles seroprevalence was observed in 18–39-year age group (Me = 59.7%; IQR = 55.9–64.6). For mumps, the lowest seroprevalence was also observed in 18–39-year age group (Me = 78.4%; IQR = 63.9–83.7). Regarding rubella, seropositivity was evenly distributed across the entire cohort: Me = 95.8% (IQR = 93.9–97.5). Among specific vaccines for immunization against measles/mumps or rubella, the mumps-measles or live monovalent rubella vaccine, respectively, was most or more frequently used. Conclusion. High measles and mumps seroprevalence among children is due to post-vaccination immunity following mass immunization, primarily with the mumps-measles vaccine. Seroprevalence in older adults is associated with childhood infections that have elicited post-infectious immunity. Rubella immunity was virtually independent of age, geographic location, or climate factors. Reduced measles and mumps seropositivity among middle-aged individuals may lead to emergence of sporadic cases of these diseases, which may require additional measures, including catch-up vaccination.

COVID-19 pandemic has caused the deaths of more than 7 million people worldwide and revealed the weakness of the global health system in the face of such challenges. In conditions of low effectiveness for disease specific prevention, an important task is to develop drugs acting to stimulate innate immunity for emergency non-specific prevention of coronavirus diseases. The aim of the study was to evaluate the effectiveness of preventive administration of an immunostimulating drug based on antigens complex of opportunistic bacteria (ACOPB, the drug Immunovac-VP-4) in protecting against SARS-CoV-2 infection. Coronavirus pneumonia was modeled by infecting golden Syrian hamsters with the Wuhan-like SARS-CoV-2 Dubrovka strain, assessing indicators such as weight dynamics, viral load and pathomorphological changes in the lungs. Preventive administration of ACOPB to hamsters in the form of a spray and by inhalation helped protect them from SARS-CoV-2 infection and its pathogenic effects. The efficacy of the drug was manifested in protecting hamsters from weight loss, a decrease in viral reproduction in the lungs and the absence of pathological morphology changes in lung tissue. Thus, animals treated with ACOPB in the form of a spray or by inhalation on day 3 post-infection gained weight, average of 4.2±3.0% (p < 0.05) and 8.8±1.3% (p < 0.001), while the animals of the viral control lost 5.6±2.8% weight. The use of ACOPB reduced virus titer in the lungs of animals by more than 2.5 lg. In addition, in patients with moderate COVID-19, the clinical effect and effect of ACOPB on the level of secretory immunoglobulin A (sIgA) in the upper respiratory tract were studied. The use of ACOPB as part of the complex therapy of patients with COVID-19 was associated with increased sIgA level in the nasal and pharyngeal areas of the upper respiratory tract from day 1 to day 30 follow-up as well as improved patient clinical condition. Thus, the mucosal immunity formed with the use of ACOPB suppresses virus reproduction in the lungs and promotes recovery of COVID-19 patients. The results showed that the ACOPB is of interest for further research as a means of emergency prevention and treatment in new coronavirus infection.

The human body and its microbiota are closely related to each other and are in dynamic equilibrium, being a single ecological system. The study involved 59 volunteers divided into 2 age groups: group 1 — from 20 to 39 years old and group 2 — from 40 to 59 years old, with a history of inflammatory diseases of the oral mucosa and periodontal tissues. According to the survey results, a higher risk of developing oral dysbiosis followed by an inflammatory process was revealed in group 2. In the conducted study, autochthonous species such as L. plantarum, L. paracasei, and L. fermentum prevailed in the digestive tract of the Tyumen residents. The authors proved that a high degree of seeding of 10⁷ CFU/ml of L. paracasei in group 1 individuals is a marker for normobiota, whereas L. fermentum and L. rhamnosus are indicators of dysbiosis in this biotope. No such pattern was found in group 2 patients. Low rates of Lactobacillus spp. up to 10⁴ CFU/ml indicates an imbalanced microbiota composition and indicates health issues. In inflammatory diseases of the oral cavity, a specific lactobacillus deficiency was observed in all subjects, regardless of age. In dental lesions of the oral cavity, two strains were found to prevail: L. fermentum and L. plantarum. The isolation of these lactobacillus strains in the studied pathological processes proves their indicator etiological significance. Presumably, the species diversity of Lactobacillus spp. in patient oral cavity was influenced by comorbidities in the anamnesis. The study of the species composition for bacterial and fungal associations in the gastrointestinal tract and oral cavity allowed to determine that the presence of certain species of Lactobacillus spp. correlates with detected pathogenic and opportunistic microorganisms. It is verified that, regardless of the biotope, L. fermentum species is as an indicator of the dysbiotic microsymbiocenosis.