Vol 13, No 3 (2023)

Acute post-streptococcal glomerulonephritis usually occurs as a complication after a streptococcal infection due to untimely or inadequate antibiotic therapy. The etiology of post-streptococcal glomerulonephritis has been studied rather comprehensively. Today, both clinicians and microbiologists do not deny the dominant role of Streptococcus pyogenes (streptococcus attributed to serological group A, GAS). Usually, emergence of acute post-streptococcal glomerulonephritis (APSGN) is associated with the so-called GAS-related "nephritogenicity" often judged by appearance and accumulation of antibodies to the antigens and extracellular products of streptococcal cells in patient blood. This interpretation is quite loose and most likely evidence about a link to the bacterial strain, rather than its nephritogenicity. Many studies refer and still attribute a leading role of "nephritogenic" factors to various streptococcal antigens and related biologically active products. Streptococcal nephritogenic factors include cross-reacting antigens, streptokinase, cysteine proteinase, endostreptosin – a GAS cell membrane protein as well as plasmin-tropic enzyme glyceraldehyde-3-phosphate dehydrogenase. Nephritogenicity of all such streptococcal products is suspected to result from the fact that they are found in renal biopsies like specific patient blood serum antibodies. Regarding a term of nephritogenicity, it has been evidenced that it cannot be attributed to any specific streptococcal cell product. This review attempted to analyze a number of bacterial products as starting factors triggering this process. APSGN can be reproduced experimentally in rabbits by intravenous administration of a heat-killed Streptococcus pyogenes culture. In our experiments, strains of serotypes 1, 4, 12, 15, 22 were used. They produced M-proteins and had the ability to bind human and rabbit immunoglobulin G by interacting with the Fc part of the IgG molecule. In numerous series of experiments, evidence was obtained regarding the initiating role of GAS IgGFc-receptor proteins in developing APSGN. Recent studies confirmed the role of streptococcal IgGFc-binding proteins in the initiation of glomerulonephritis after animals were inoculated with temperature-killed IgGFc-positive GAS. This approach excluded a large group of bacterial extracellular agents from the list of APSGN-initiating candidates. An unconventional view on the pathogenesis of GAS-infection-coupled complications may allow approaching their prevention or new treatment strategies.

Vaccination is the most effective method of influenza prophylaxis resulting in reduced frequency and severity of complications. Currently, for the prevention of influenza, inactivated split and subunit vaccines as the safest and promoting formation of protective level of strain-specific virus neutralizing antibodies are used. It is known that not all inactivated vaccines are effective enough for select human groups. While nowadays the level of public health is low, there is a need to improve the effectiveness of vaccines that should activate all chains of the immune system. In order to enhance intensity of influenza virus strain-specific antibody production, adjuvant vaccines exerting other mechanisms to activate humoral and cellular immunity compared to non-adjuvant vaccines have been used. The aim of the study was to examine lymphocyte immunophenotype in 27 healthy donors treated with polymer-subunit (immunoadjuvant) and non-adjuvanted split and subunit influenza vaccines.

Materials and methods. Peripheral blood lymphocyte subpopulations were studied in vitro by flow cytometer FC-500 Cytomics (Beckman Coulter, USA) using FITC- and PE-labeled monoclonal antibodies (mAbs).

Results. All examined influenza vaccines activate the effectors of cellular immunity, increasing the number of NK-cells (CD16/56), NKT-lymphocytes (CD3/CD16/56), B-lymphocytes (CD45/CD20), activated (CD3/HLA-DR) and cytotoxic (CD8/HLA-DR) T-lymphocytes, as well as cells bearing early activation marker (CD45/CD25). Among them the immunoadjuvant vaccine showed the greatest potential to induce cellular response eliciting regulatory mechanisms that prevent hyperactivation, stimulating growth of NK (CD16/56), NKT-cells (CD3/CD16/56), B-lymphocytes (CD45/CD20), activated (CD3/HLA-DR) and cytotoxic (CD8/HLA-DR) T-lymphocytes, T-regulatory cells (Tregs, CD4/CD25/Foxp3).

Conclusion. Vaccination against influenza besides the formation of specific antibodies render a transient, immunomodulating effect that is more noticeable after immunoadjuvant vaccine. It can be assumed that vaccination of people with dysfunctions of the immune system an additional prophylactic effect will be observed.

Saposins (Sap) are a subgroup of glycoproteins belonging to the Saposin-Like Proteins family. They are generated by the proteolytic processing of the common precursor prosaposin. Saposins localize primarily in the lysosomes and are required for the catabolism of glycosphingolipids. Saposins are involved in the presentation of lipid mycobacterial antigens on CD1 molecules. SapD is the most abundant saposin in normal tissues, where its concentration is three times higher than that of other saposins. SapD promotes the hydrolysis of ceramide by acid ceramidase in vivo, as evidenced by the accumulation of 〈-hydroxyl-ceramide in the kidneys and cerebellum of SapD-deficient mice. Accordingly, SapD-deficient animals show renal tubular degeneration and hydronephrosis, as well as progressive loss of Purkinje cells in the cerebellum, leading to ataxia. To date, no hereditary SapD deficiency has been identified in humans.Previously we had shown that macrophages derived from SAPD knockout mice suppress the growth of M. tuberculosis to a lesser extent than macrophages from wild-type mice. Moreover, compensation for the deficiency of SapD in knockout cells led to the restoration of their bactericidal function. Thus, SapD is an important component in the anti-TB immune response. However, it is not clear how SapD deficiency affects the in vivo antituberculosis immune response. In the model of experimental tuberculosis infection, it was shown that five weeks post infection the mycobacterial load in the lungs and spleens was significantly higher in SapD-ko mice than in wild-type mice. Analysis of the lung tissue cellular composition showed the differences between SapD-ko and B6 mice. Thus “naive” SapD-ko mice are characterized by a larger quantity of macrophages compared to B6 mice. It was also shown that five weeks after infection, SapD-ko mice differ from wild-type mice in a more pronounced neutrophilic infiltration of the lung tissue. A study of the propensity for apoptosis of cells in the lung tissue of SapD-ko mice showed that the content of apoptotic cells in the lungs of SapD knockout mice three weeks after infection was significantly higher than in wild-type B6 mice. Thus, SapD deficiency leads to a significant increase in inflammation during experimental tuberculosis infection, and also affects the predisposition of lung cells to apoptosis.

Modern methods of vaccination have confirmed their high effectiveness in fighting against the pandemic of a novel coronavirus infection. However, the use of various types of vaccines requires studying the effectiveness of the post-vaccination immune response (PIO), first of all, assessing the specificity and amount of production of antibodies to the surface and internal antigens of the SARS-CoV-2 virus, in particular, after the use of the most promising domestic vaccine “Gam-Covid-Vac” (“Sputnik V”). In particular, the data on the effectiveness of PVIR (increased antibody level) for the most promising domestic vaccine “Gam-Covid-Vac” (“Sputnik V”) need to be confirmed. It is also necessary to evaluate the effectiveness of the laboratory methods used for this purpose. To assess the effectiveness of PVIR, samples of biomaterial (blood serum) obtained on the 22–25 day after inoculation of the second component of the vaccine from 202 “Sputnik V”-vaccinated, not preimmunized subjects, lacking antibodies to SARS-CoV-2 before vaccination, were examined. The levels of IgG and IgM antibodies to the surface and nucleocapsid antigens of the SARS-CoV-2 virus were determined using several semi-quantitative and quantitative methods and reagent kits from national and foreign manufacturers. To assess the diagnostic effectiveness of the methods, a comparative analysis of the specificity and sensitivity of all the laboratory methods used and a data correlation for various quantitative methods (using the Spearman correlation coefficient) between antibodies specific to the full-sized trimerized S-protein and the receptor-binding domain (RBD) of the SARS-CoV-2 S-protein were carried out. During the study, it was determined that all the reagent kits used to study IgG antibodies against SARS-CoV-2 S-protein and S-protein RBD showed maximum (100%) specificity in in the majority subjects (from 186 to 202 samples). The relevance of the data (comparative specificity), both for semi-quantitative and quantitative ELISA as well as for both ILA test systems regarding qualitative characteristics (“positive”–”negative”) was also close to the maximum magnitude (98.4–99.4%). A post-vaccination immune response during Sputnik V vaccination analyzing production of specific IgG antibodies was observed in 98.9% of all vaccinated subjects. IgG antibody range was studied to assess related “protective” level. Data are presented that a “protective” level of more than 150 BAU/мл was observed in 59.3–90.5% of the subjects, above 500 BAU/ml — in 22.0–52.4% of the subjects, depending on the method used and the set of reagents. Based on the data obtained, it is concluded that all the methods and kits of reagents used, including domestically manufactured semi-quantitative tests, can be considered adequate to assess effectiveness of the post-vaccination immune response analyzing production of SARS-CoV-2-specific antibodies.

The 2019 coronavirus infection (COVID-19) has not been considered as a solved issue for public health. Pregnant women and newborns are specifically vulnerable to COVID-19 infection compared to older children and healthy young adults. Virtually no data on relation between diverse arms of immunity in patients in neonatal period and coronavirus infection are available. The obtained results can contribute to a better understanding of the pathogenetic mechanisms on reactivity of immune processes in young patients and corresponding formation of approaches for prevention and correction of such disorders. The aim of the study was to determine magnitude of specific altered parameters in immune system and their relation with lipid peroxidation parameters in COVID-19 newborns. Two groups of newborns (mean age 4±3.1 days) were examined: SARS-CoV-2-positive (COVID-19 patients, n = 44) and negative (control group, n = 80) PCR test of nasopharyngeal swab. All newborns were assessed for specific indicators of peripheral blood immune status and lipid peroxidation activity. The concentration of Th1-pro-inflammatory cytokines and Th2-anti-inflammatory interleukins was assessed by enzyme immunoassay method (a panel of monoclonal antibodies). Spectrophotometric, fluorometric and enzyme immunoassay methods to evaluate the lipid peroxidation system were used. According to our data, newborns with COVID-19 vs. healthy newborns had decreased CRP, pro-inflammatory cytokines — TNFα, IL-1β, IL-6, IL-8, and anti-inflammatory factor (IL-4). Change in lipid peroxidation system in children with COVID-was 19 related to higher level of DC, KD and CT, TBARs, increased SOD activity and reduced GPO. Numerous intersystem dependencies in the group of newborns with COVID-19 (CRP — Total AOA, IL-4 — KD and CT, IL-4 — TBARs, IL-4 — Total AOA, IL-4 — SOD, IL-8 — SOD, IFNγ — GSH) were noted. It can be concluded that in newborns with COVID-19, changes in the immune system are nonspecific and are accompanied by an increased intensity of lipid peroxidation reactions against the background of reduced values of pro- and anti-inflammatory cytokines. These results may contribute to a more accurate assessment of intensity and dynamics of emerging neonatal coronavirus infection, which should be an important arm in preventing subsequent complications.

Patients with pulmonary tuberculosis and multiple pathogen resistance (MDR) develop persistent disorders of the intestinal microbiome during prolonged multicomponent chemotherapy requiring correction. However, there is limited data on the use of bacterial drugs in patients with tuberculosis followed by assessing their effectiveness. The aim of the study was to evaluate changes in the intestinal microbiome after a course of probiotics along with anti-tuberculosis chemotherapy in patients with MDR tuberculosis.

Materials and methods. The design — a prospective small-cohort study (n = 30). Patients with pulmonary tuberculosis received anti-tuberculosis drugs according to the IV or V regimen, the median of the doses taken was 34.5 (30; 57.5); gastrointestinal syndrome was recorded in all study subjects. Probiotic therapy was applied by using a preparation containing Bifidobacterium bifidum and B. animalis and Lactobacillus casei, L. plantarum, L. delbrueckii subsp.bulgaricus, L. acidophilus. The course of therapy comprised 21 days,1 capsule twice a day. Before and 7 days after probiotics therapy, studies on composition of the intestinal microbiota were carried out, the frequency of virulence factors Enterococcus spp., Staphylococcus spp., Candida spp. was examined; fatty acid composition and activity of enterococcal organic acid production were studied.

Results. After a course of probiotics, a significant increase in lactobacillus titers was recorded from 5.2 (4.0; 6.0) to 6.1 (6.0; 8.0) lg CFU/g (p = 0.05). The frequency of mucosal colonization by Candida fungi and lactose-negative Escherichia decreased by 2-fold (p = 0.001) and 3-fold (p = 0.05), respectively. The frequency of detected virulent strains significantly decreased: hemolysin-producing staphylococci — by 9 times (p = 0.009), enterococci with gelatinase activity — by 6 times. E. faecalis membrane oleic acid level significantly increased (C9-C18:1) (p = 0.03). In E. faecium, cis-7-palmitoleic acid (C7-C16:1) and oleic (C9-C18:1) fatty acid level increased by 2-fold (p = 0.05), and for linoleic acid (C18:2) — by 4 time (p = 0.04) accompanied by elevated acid formation by 1.5 times.

Conclusion. A single course of probiotic therapy in patients with pulmonary tuberculosis leads to qualitative microbiome changes, which are characterized by decreased levels of conditionally pathogenic microorganisms with virulent properties and altered composition of the enterococcal cell membrane accompanied by their increased biochemical activity.

The article presents a description of the current tick-borne infection epidemiological situation in the south of Russia from the years 2013 to 2022, proposes a new approach to develop “forecasting” models for morbidity dynamics of Astrakhan rickettsial fever (ARF) and Crimean hemorrhagic fever (СCHF) in the Astrakhan region and presents data assessing 2022 “explaining” models for the Stavropol Territory and Astrakhan Region. Materials and methods. A comprehensive research was performed using epidemiological analysis and non-parametric statistical methods. The data assessing tick-borne infections epidemic process manifestations were retrieved from ARF and CCHF morbidity databases (developed as a project) and documents of infectious disease focus epidemiological examination provided by the departments of Rospotrebnadzor in the subjects of the Southern and North Caucasian Federal Districts. Morbidity models were developed using the Bayes’ theorem and Wald’s sequential statistical analysis, with a preliminary calculation of indicators informativeness by the Kullback method. The values of climatic factors from the database of the Center for Collective Use “IKI-monitoring” of the Space Research Institute of the Russian Academy of Sciences were used. Results. The results of the study indicate persistence of serious epidemiological situation regarding rickettsiosis of the tick-borne spotted fever group, Q fever, tick-borne borreliosis and CCHF in the south of Russia. Almost all tick-borne infections nosological forms in children under 14 years (including young children and infants) were widely involved in the epidemic process, which belong to patients at risk for a complicated disease course due to complicated diagnostics and treatment. The annual registration of tick-borne infections cases in the resort areas, with the subsequent occurrence of imported cases in other, including non-endemic regions poses a serious problem. The proposed “forecasting” models allow to predict the CСHF and ARF morbidity for each administrative district of the Astrakhan region with up to 91.7% accuracy. The “explaining” models CСHF accuracy for the Stavropol Territory and Astrakhan Region, when tested in 2022, was 88.5 and 83.3%, respectively, for ARF — 91.7%. Conclusions. The further continuation of “forecasting” and “explaining” models verification for planning preventive measures and propose similar steps for tick-borne borreliosis and Q fever to epidemiological tick-borne infections to stabilize situation in the south of Russia.

The pathogenesis of rosacea is not fully understood. In this disease, the release of inflammatory molecules and overgrowth of skin-colonizing microorganisms, including fungal microbiota, are noted. The study of the frequency of occurrence and the nature of the spectrum of sensitization to fungal allergens in patients with rosacea is of particular interest and accounts for relevance of the study. Purpose of the study: to analyze the frequency of occurrence and the nature of the spectrum of sensitization to fungal allergens in patients with rosacea.

Materials and methods. The study included patients with rosacea aged 18 to 60 years (group 1, n = 31). All patients underwent a specific allergic examination: collected allergic history, skin prick testing using the following allergens: nutritional yeast, Candida albicans, Alternaria alternate, Aspergillus fumigatus, Cladosporium herbarum, Penicillium notatum (Allergopharma, Germany). Concentration of total immunoglobulin E (IgE) and eosinophilic cationic protein in blood serum was measured in indirect immunofluorescence analysis with Thermo Scientific Multiskan FC semi-automatic analyzer. Statistica 8.0 software package was used for statistical analysis.

Results. Analysis of the features of the spectrum of sensitization to fungal allergens in the group of patients with rosacea showed that the most significant allergens are Cladosporium herbarum (74.2% of patients) and Candida albicans (58.1%). Sensitization to nutritional yeast and Penicillium notatum was detected in almost half of the patients. The concentration of total immunoglobulin E in blood serum in the group of patients with rosacea was 79.4 IU/ml [23.4; 105.1], in the control group — 45.1 IU/ml [23.4; 144.0]. The concentration of eosinophilic cationic protein in blood serum in the group of patients with rosacea was significantly higher compared to the control group: 50.3 ng/ml [43.0; 62.0] and 7.9 ng/ml [4.6; 27.1], respectively. After skin prick testing with fungal allergens, patients with rosacea were prescribed an individual elimination diet with the exclusion of causally significant allergens for a period of 1 month. In 61.2% (n = 19) of cases in patients with rosacea, a positive elimination effect was noted: a significant decrease in the severity of erythema, papules and pustules in the face.

Conclusion. Thus, the study revealed a high incidence of fungal allergy and established the features of the spectrum of sensitization to fungal allergens in patients with rosacea. The most significant fungal allergens in rosacea are fungi of the genus Cladosporium herbarum, Candida albicans, Penicillium notatum as well as nutritional yeast.

In recent years, there has been increasing interest in using bacteriophages in the complex therapy of some infectious diseases. Objectively, it is related to the spread of antibiotic resistance and a small number of side effects triggered by phages applied locally and parenterally. Yersiniae are no exception to this rule, but their interaction with virions has not been studied thoroughly. In three types of lytic Yersiniae bacteriophages are used for diagnostic purposes, which differ in specificity, virulence, and morphological features. We evaluated the interaction force between phages and bacteriae by optical trapping.

Materials and methods. Live Yersinia pseudotuberculosis and Y. pestis cells with different LPS structure and preparations of three bacteriophages — Pokrovskaya’s phage, d’Herelle’s phage (also named as the pseudotuberculosis phage) and the phage L-413C were used. The Pokrovskaya’s phage is well studied and widely used in diagnostics, but the mechanism of its adsorption on Y. pestis and Y. pseudotuberculosis cells is not well-understood. The phage L-413C lyses plague bacteria, while d’Herrel’s phage can lyse both pathogens. Virions were linked to the surface of aminated glass. Optically trapped microbial cells were approached to the glass surface and then retracted in the opposite direction. The amplitude of the leap was recalculated into force through calibration coefficients. The primary data were processed in the program “R”; statistical analysis was performed using “Matlab 7.0” and “Statistica 12”

Results and discussion. The analysis of histograms revealed the presence of a specific component in the «Y. pseudotuberculosis–d’Herrell’s phage» (Fmean = 7.46±3.52 pN) system, as well as in all pairs involving plague microbe. In the latter case, the interaction forces were comparable: 8.64±3.83 pN for d’Herelle’s phage,11.03±4.22 pN for Pokrovskaya’s phage, and 10.42±4.79 pN for phage L-413C. The average detachment force from the substrate treated with bovine serum albumin (BSA) was comparable for both cell types. Our results convincingly prove an opportunity for using the optical trapping to estimate interaction force in other «bacterium–phage» systems.

During the COVID-19 pandemic, there have emerged publications about various skin manifestations mainly caused by the related coronavirus, also including some case reports on dermal drug-related adverse reactions. In Armenia, the doctors in COVID-19 hospitals periodically consulted with allergists-immunologists regarding allergic conditions that many patients already suffered on admission or manifested after it. We present the series of three most interesting drug-induced cases with various skin manifestations in patients with COVID-19 pneumonia who requited antibiotic therapy. The causative significance of antibiotics was assessed according to Naranjo’s algorithm. In the first case (a 58-year-old female patient), a diagnosis of maculopapular exanthem was made based on the clinical picture. Although the coronavirus per se can result in similar manifestations, previous history of allergic reaction to ampicillin led to the conclusion that ceftriaxone (both are beta-lactam antibiotics) was the most probable cause. The second case (a 53-year-old male patient), clinically manifested as vasculitis, caused some difficulties because this is quite often skin manifestations related to SARS-CoV-2, and is rarely induced by medications. Taking into account the history of reaction to beta-lactam antibiotic, as well as the fact that the patient took amoxicillin without a prescription before hospitalization and with overt skin lesions at that time, amoxicillin was assessed as a possible cause. In the third case (a 64-years-old female patient), diagnosed with a bullous drug-induced skin eruption, despite isolated cases of such lesions can be manifestations of SARS-CoV-2 infection, moxitec (fluoroquinolone antibiotic) was assessed as the most probable cause, especially taking into account herpes in history. According to current recommendations, an issue of drug tests was discussed with all three patients to confirm the causative significance of indicated drugs and/or to select an alternative drug, if necessary. In this regard, the subjects were included in the database of patients with severe drug hypersensitivity reactions by their informed consent.

The aim of the study was to increase diagnostic sensitivity for identification of A. baumannii bv. tryptophandestruens bacteria and assess prevalence of this biovar and its subbiovars among A. baumannii clinical isolates. There were examined 210 primary strains of A. baumannii isolated in 2021–2022 at Bacteriological Laboratory of the Military Medical Academy named after S.M. Kirov, of which 42 strains were A. baumannii bv. tryptophandestruens. Tryptophandestruens biovar bacteria were identified by chromogenic biotransformation of sodium benzoate on a dense nutrient medium (g/l): peptone enzymatic 5.0; NaCl 5.0; FeCl₃ 6H₂O (10% aqueous solution) 0.1–1 ml; bromothymol blue (1.6% aqueous solution) 3 ml; agar 15.0; NaOH (4% solution) 2.6–3 ml; distilled water 1 l; all components were dissolved by heating and added with sodium benzoate (CAS 532-32-1) 1.0–2.0; adjusted pH 7.2±0.2; sterilized at 121°С, poured into Petri dishes. Bacteria of subbiovars A and B of biovar tryptophandestruens were identified by chromogenic biotransformation of L-tryptophan using the same nutrient medium supplemented with L-tryptophan (1.0–2.0 g/l) instead of sodium benzoate. Both nutrient media were used simultaneously. The A. baumannii cultures studied were seeded with a loop on the media sectors in the form of a plaque, incubated aerobically at 37°С for 18–24 hours, and analyzed final data as follows: the presence of a dark brown color zone of the nutrient medium around bacterial lawn on sodium benzoate- and L-tryptophan-containing medium indicated detection of subbiovar A of the tryptophandestruens biovar; in case of dark brown zone on sodium benzoate- but not L-tryptophan-containing medium around bacterial lawn identified biovar tryptophandestruens subbiovar B. The study revealed for the first time the chromogenic biotransformation of sodium benzoate (benzoic acid) and its importance as a marker for the biovar tryptophandestruens A. baumannii. Two subbiovars A and B of the tryptophandestruens biovar were found. A method was developed to identify the biovar tryptophandestruens A. baumannii and its subbiovars A and B by chromogenic biotransformation of sodium benzoate and L-tryptophan, which enhances diagnostic sensitivity by detecting the subbiovar B. The frequency of tryptophandestruens biovar distribution among primary clinical isolates of A. baumannii in 2021–2022 was determined: out of 210 strains of A. baumannii were 42 (20.0±3.5%) strains of bv. tryptophandestruens including subbiovar A — 27 (12.9±2.3%), subbiovar B — 15 (7.1±1.7%).