Journal of microbiology, epidemiology and immunobiology

Introduction. The human immunodeficiency virus (HIV) remains a global health challenge. The TRIM22 gene, which encodes a protein with antiviral activity, is a promising candidate for research, but its role in the pathogenesis of HIV infection in population of the Russian Federation has not been previously studied.

The aim of the study was to analyze the polymorphic variants rs7935564 (N155D) and rs1063303 (T242R) of the TRIM22 gene in HIV-infected individuals in the Northwestern Federal District.

Materials and methods. Polymorphic variants rs7935564 (N155D) and rs1063303 (T242R) of the TRIM22 gene were analyzed in groups of HIV-infected individuals with virological failure of antiretroviral therapy (n = 378) and practically healthy individuals (n = 319). Genotyping was performed using the polymerase chain reaction method followed by sequencing. Statistical analysis included testing for Hardy-Weinberg equilibrium of genotype distributions, assessing associations under 3 inheritance models (dominant, recessive, additive) with odds ratio (OR) and 95% confidence interval (CI) calculation, linkage disequilibrium analysis, and haplotype frequency analysis.

Results. The distribution of genotypes for the analyzed polymorphic variants was conformed to Hardy-Weinberg equilibrium expectations (p > 0.05). A significant association was found between the G allele of the rs7935564 polymorphism and the presence of HIV infection in both recessive (OR = 1.76) and additive (OR = 1.37) inheritance models. For polymorphism rs1063303, a significant association was observed only in the dominant model (OR = 1.40). Moderate linkage disequilibrium was found between the loci (D' = 0.4478; r² = 0.1572; p < 0.001). The G-G haplotype (rs7935564_G — rs1063303_G) was associated with the presence of infection (OR = 1.57).

Conclusion. In the Russian population, the polymorphic variant rs7935564 (N155D) of the TRIM22 gene is a significant genetic factor associated with HIV infection, while the results for rs1063303 (T242R) were statistically ambiguous. The association of the G-G haplotype with the presence of infection suggests a potential synergistic effect of these alleles. The data obtained highlight the importance of considering a population genetic background when evaluating the genetic determinants of the interaction between HIV and the host organism.

The aim of this study was to investigate the effect of the innovative Russian antibacterial drug Fluorothiazinone, an inhibitor of the type III secretion system and flagellar function, on the virulence properties of urinary tract infection (UTI) pathogens.

Materials and methods. Clinical isolates of Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa species were obtained from 4 patients with recurrent UTI. Cytotoxicity analysis was performed on HeLa cells using the CytoTox 96 kit. Bacterial flagellar motility was assessed in 0.25% agar by measuring the zone of motility. Biofilms were cultivated in 96-well plates and stained with crystal violet and Congo red. Biofilm structure was assessed by microscopy, and the bacterial biofilm and exopolysaccharide matrix were quantified by measuring the optical density of the dye bound to the biofilm. Intracellular development was studied in PC-3 cells by determining the number of intracellular bacteria using a cell lysate plating method and an immunochemical method involving staining the bacteria with specific antibodies.

Results. The Fluorothiazinone antibacterial specifically inhibited the cytotoxicity and motility of E. coli and P. aeruginosa. For K. pneumoniae, susceptibility to Fluorothiazinone was observed, associated with the suppression of cytotoxicity. For all the isolates studied, inhibition of biofilm formation on an abiotic surface was demonstrated. For E. coli and K. pneumoniae, a significant decrease in intracellular replication within human prostate adenocarcinoma cells and suppression of intracellular bacterial community formation were observed.

Conclusion. Fluorothiazinone disrupts mechanisms that contribute to pathogen persistence in the formation of chronic UTI, including biofilm formation on abiotic surfaces such as catheters, stents, and drains, and the formation of intracellular bacterial communities and dormant intracellular reservoirs.

Introduction. During the COVID-19 pandemic, the development of preventive vaccines, including those based on new platforms, became extremely relevant. One such platform is vaccines, which combine, for example, DNA and protein components into a single vaccine.

The aim of this study was to investigate the immunogenicity of a DNA vaccine encoding a polyepitopic T-cell immunogen of the SARS-CoV-2 virus, combined with the recombinant RBD protein (the receptor-binding domain of the SARS-CoV-2 virus S protein, Wuhan-Hu-1 strain) conjugated to a polycationic carrier – polyglucin-spermidine (PGS), and to assess the contribution of individual components to the development of an immune response in BALB/c mice.

Materials and methods. To create the DNA vaccine (pBSI-COV-Ub), we used a strategy of designing an artificial polyepitope immunogen consisting of conserved immunodominant fragments of various structural proteins of the SARS-CoV-2 virus, containing a large number of T-lymphocyte epitopes: helper and cytotoxic. The recombinant RBD protein was conjugated with the polycation PGS, and upon mixing it with DNA, it formed the vaccine complex CCV–BSI, whose immunogenic properties were investigated in this work.

Results. Immunization of BALB/c mice with the CCV–BSI combined construct resulted in the induction of high antibody titers with neutralizing activity against live SARS-CoV-2 virus, as well as the formation of a virus-specific T-cell response, as demonstrated by ELISA, neutralization assay and ELISpot. It has been shown that the protein component contributes to the humoral immune response, while DNA contributes to the cellular immune response. Administration of the recombinant RBD protein led to the induction of only antibodies, administration of the DNA vaccine led to the induction of only a T-cell response, and administration of the combined preparation led to the induction of both a humoral immune response and specific T cells.

Conclusion. The unique combination of DNA and protein within a single vaccine construct allows for overcoming the limitations of each of these vaccine types and leads to the induction of both arms of immunity. The protein component can be replaced according to the current viral strain, and a universal T-cell immunogen can provide a response to a wide range of circulating variants. This platform can be further used to develop vaccines against various highly variable viruses.

Introduction. The two-component BvgAS system regulates the transcription of the pathogen's virulence genes and plays a key role in the pathogenesis of whooping cough, an anthroponotic infectious disease. Currently, the factors affecting the BvgAS system of Bordetella pertussis bacteria in the human organism have not been studied in practice. It is known that disruption of the bvgAS operon structure leads to phase modulations and changes in virulence. IS-elements intergation into the bvgAS operon and other virulence genes of B. pertussis bacteria is important mechanism in regulating their expression, potentially leading to the long-term persistence of this pathogen in the human body.

Aim. Identification and description of spontaneous IS-elements insertions in B. pertussis into bvgAS, cya and fhaB virulence genes responsible for hemolytic activity during in vitro bacterial cultivation.

Materials and methods. B. pertussis strains from the collection of the N. F. Gamaleya National Research Center for Epidemiology and Microbiology were used: virulent B. pertussis 475 strain and its isogenic attenuated strain B. pertussis 4MKS; virulent B. pertussis strain Tohama I and its avirulent mutant B. pertussis 347. Bacteria were cultivated on casein-charcoal agar with blood addition. The formation of haemolysis zones was assessed visually. PCR, real-time PCR and sequencing were used for the genetic characterization of the obtained insertion mutants.

Results. B. pertussis mutants containing insertions of IS-elements in fhaB and bvgAS genes with impaired hemolytic activity (Hly^– phenotype) have been isolated in vitro, as well as B. pertussis mutants that retained hemolytic activity (Hly⁺ phenotype), containing IS-elements in a previously undescribed orientation in the bvgAS gene. The frequency of insertional mutant formation depended on conditions of cultivation and bacteria genotype.

Conclusion. Arguments are made for the hypotheses about the IS-elements involvement in B. pertussis bacteria transition to a state of reduced virulence, which provides the possibility of long-term persistence of this pathogen in the human body.

Introduction. The registration of sporadic cases of glanders in horses in Russia, caused by Burkholderia mallei, highlights the importance of developing genotyping algorithms for this pathogen. The MLVA method (multilocus-variable tandem repeat analysis), based on a comparative analysis of the number of variable tandem repeats (VNTRs), remains a promising genotyping tool. As the number of whole-genome sequences in international databases increases, the informative value of VNTR loci changes, necessitating a revisiting of existing typing schemes.

The aim of this study was to assess the feasibility of including the VNTR locus BPSS1974^#I in the MLVA-6 scheme for intraspecies differentiation of B. mallei.

Materials and methods. The study of 64 strains of B. mallei was conducted in silico and in vitro using MLVA, differentiating region amplification, whole-genome sequencing, and bioinformatic analysis.

Results. Genotyping B. mallei using the MLVA-6 scheme failed to determine in silico VNTR profiles of 13 strains from the GenBank NCBI database for one or more loci due to low read coverage of the corresponding genomic regions or their complete absence (null alleles). The effective number of alleles (ne) and the polymorphic information content (PIC) index for the MLVA-6 scheme loci ranged from 3.842–8.103 and 0.740–0.877, respectively. The potential for including the VNTR locus BPSS1974^#I in this scheme was determined based on the molecular stability of the motif within it and a high values for ne and PIC, which were 4.299 and 0.767, respectively. VNTR profiles of the collection strains at locus BPSS1974^#I were identical to the corresponding strains in the GenBank database. The results of the cluster analysis using a combined MLVA-6 scheme and the BPSS1974^#I locus were consistent with the phylogenetic reconstructions obtained using other molecular genetic methods.

Conclusion. The VNTR locus BPSS1974^#I can be considered a marker, the inclusion of which in the MLVA-6 scheme will improve the accuracy of genotyping and the determination of the regions of origin of newly isolated B. mallei strains.

Introduction. Protective gloves are widely used in medicine to provide biological protection for patients and medical staff. However, if gloves are used improperly, there is a risk of healthcare-associated infections (HAIs) for both staff and patients. A significant problem is the resulting growth in medical waste and its disposal. Therefore, developing new approaches to ensure maximum protection for staff and patients, and minimize the risk of infection, by creating protective gloves based on biodegradable polymer materials with an antimicrobial coating, is an urgent epidemiological and environmental objective.

This paper discusses modern technologies and emerging issues in the creation of new materials for protective gloves with antimicrobial properties. These materials can be made using guanidine derivatives, quaternary ammonium compounds (QACs), chlorinated phenols, essential oils, iodine compounds, silver salts, metal oxides and metal nanoparticles and oxides, vegetable oil extracts, aniline dyes. The introduction of biofillers such as starch and nanocellulose will help improve biodegradability. They will also help maintain the necessary physical and chemical characteristics. The problem of synthetic rubber waste disposal can be solved by the development of new composite materials with improved biodegradation characteristics. These materials are in the form of thermoplastic elastomers (TPE), polylactide (PLA) and polylactone (PLC).

Conclusion. A review of the scientific literature revealed a significant global interest in the creation of protective gloves with antimicrobial properties made from biodegradable materials. However, in addition to directly suppressing the growth of pathogenic microflora, their use may also pose a number of problems related to their impact on human health and the ecosystem. The successful implementation of this direction hinges on the continuation of scientific research on imparting the declared properties to gloves. This research should use effective, reliable and safe technologies, as well as the development of unified methods and protocols for assessing antimicrobial activity. Once these are in place, the research can be implemented widely in practice. The production of biodegradable protective gloves offers significant potential, as it will help to reduce the risk of infection spreading in healthcare organizations and contribute to environmental protection.