The circulation of a rather wide range of pathogens of natural-focal infectious diseases transmitted by ticks was detected in West Africa at different points of time: Borrelia, Rickettsia, Coxiella, Crimean-Congo hemorrhagic fever (CCHF), Bhanja, and bluetongue viruses, etc. Current epidemiological and epizootiological situation on natural-focal infectious diseases on the territory of the Republic of Guinea is not entirely clarified.The aim of this work was to identify genetic markers (RNA/DNA) of natural-focal infectious disease agents in samples of Ixodidae ticks collected in the Republic of Guinea, and to determine the spectrum of pathogens circulating in various landscape-geographical zones of the country.Materials and methods. To conduct research on the territory of all landscape-geographical zones of the Republic of Guinea, 4695 specimens of Ixodidae ticks of 11 species were collected. Taking into account the species appurtenance, gender, phase of development, as well as the site of collection, a panel of 1645 samples was compiled. Genetic markers of Crimean-Congo hemorrhagic fever and tick-borne encephalitis viruses, as well as Borrelia burgdorferi s.l., Ehrlichia chaffeensis, Ehrlichia muris, Anaplasma phagocytophilum, Coxiella burnetii, Rickettsia of the tick-borne spotted fever (TBSF) group, and Francisella tularensis were detected using polymerase chain reaction (PCR) and reverse transcription polymerase chain reaction (RT-PCR).Results and discussion. The following markers of natural-focal disease agents were found in the Ixodidae tick suspensions: DNA of Rickettsia of the TBSF group (25.6 % of all samples studied), DNA of C. burnetii (6.2 %), cDNA of B. burgdorferi s.l. (9.1 %), and RNA of the CCHF virus (2.5 %). The listed spectrum of pathogens has been registered in all landscape-geographical zones of Guinea. Genetic markers of tularemia, anaplasmosis, ehrlichiosis and tick-borne encephalitis pathogens have not been identified in this study. The results obtained made it possible to clarify the probable spectrum of tick-borne diseases in the territory of the Republic of Guinea, determined the need for further study of the circulation of natural-focal infectious disease agents in West Africa and conducting regular epizootiological monitoring.

Emergence of various genovariants of the SARS-CoV-2 virus, which are characterized by a higher ability to spread and a more severe clinical manifestations compared to the initial variants, require molecular-genetic monitoring of strains circulating in the Russian Federation.The aim of the work was to identify the VOC SARS-CoV-2 genovariants in the territory of the Republics of Bashkortostan, Tatarstan, Udmurtia, and Samara, Penza, Saratov, Ulyanovsk, and Orenburg Regions.Materials and methods. The identification of genovariants and the determination of the type of mutations was carried out by the Sanger fragment sequencing method.Results and discussion. The study examined 298 samples of clinical material obtained from the Centers for Hygiene and Epidemiology in the Republics of Bashkortostan, Tatarstan, Udmurtia, Samara, Penza, Saratov, Ulyanovsk, and Orenburg Regions. In 17 % of cases, the variability of the SARS-CoV-2 virus was observed for one or more markers: in three samples, a new coronavirus of the B. 1.1.7 line (“British”) was detected; in a number of cases, only one mutation was detected in the virus found in samples – deletion Y144 or substitution D138Y, E484K, N501Y, and very rarely two mutations – deletion Y144 and substitution E484K. The presence of the L141-G142-V143 deletion localized in the recurrent deletion region RDR2 of the S-gene was shown in 10 % of the cases. The data obtained indicate the heterogeneity in macroorganism of the population of the new coronavirus with the deletion L141-G142-V143, which leads to a change in the antigenic structure of the virus, which probably allows the virus to evade the immune response.

Community-acquired pneumonia is a polyetiological infectious disease of bacterial or viral nature. In most cases, it is caused by pathogens such as Streptococcus pneumoniae, Mycoplasma pneumoniae, Haemophilus influenzae, Chlamydophila pneumoniae, Staphylococcus aureus, Legionella spp. However, despite that a wide range of modern diagnostic methods have been introduced into laboratory practice, the etiology of the disease can be determined only in 40–60% of cases. Here, we analyzed the causative agents of community-acquired pneumonia and relevant markers samples of clinical material collected from patients undergoing treatment in the medical facilities of the city of Saratov and the Saratov Region during the period from July to August, 2020, coupled to increase number of cases of new coronavirus infection COVID-19. Clinical material (oropharyngeal swabs, saliva, sputum, blood and blood serum) was obtained from 129 patients and investigated by using microbiological, immunoserological and molecular genetic methods. For this, there were used transport and nutrient media, diagnostic drugs, reagents, discs with antibacterial domestic and foreign drugs registered in the Russian Federation. As a result, 82 (63.6%) patients were found to have markers of the pathogen COVID-19 (viral RNA or specific antibodies of IgM and/or IgG classes), whereas 42% of cases had overlapped RT-PCR and ELISA data. There was a predominance of severe clinical forms of the disease in the group of patients with pneumonia caused by SARS-CoV-2 virus (17.1%), compared with pneumonia of another etiology (12.8%). No marked differences in specific pattern of the accompanying microflora and its sensitivity to antibacterial agents were observed in persons with/without markers of COVID-19. While being examined by bacteriological methods, S. aureus, K. pneumoniae, S. pneumoniae, M. pneumoniae, Acinetobacter spp., both in monoculture and in associations, were isolated from samples of clinical material collected from the majority of patients. In 49.6% of cases, pathogenic microflora, including pathogens causing community-acquired pneumonia, has not been identified, which may be due to the use of antibacterial drugs before the collection of clinical material and treatment applied due to comorbid chronic diseases.

The aim of the work was to analyze the results of investigating the field material obtained from natural plague foci of the Kyrgyz Republic (KR) in 2023, using modern diagnostic technologies.Materials and methods. 1435 biological samples from the Tien Shan, Alai and Talas high-mountain foci of the Kyrgyz Republic were studied using conventional methods of laboratory diagnosis of plague: microbiological, immunological, biological; as well as modern molecular-genetic methods. Testing of the obtained samples for the presence of plague pathogen DNA was carried out using RT-PCR; and the presence of antibodies to the plague microbe was detected by enzyme-linked immunosorbent assay (ELISA). Molecular identification of Yersinia pestis strains according to their appurtenance to subspecies, biovars, and phylogenetic lineages was performed by RT-PCR using the method of identifying single-nucleotide substitutions based on the analysis of melting curves of products.Results and discussion. An approach to the molecular identification of Y. pestis strains from plague foci of the KR has been developed and validated through identifying singlenucleotide substitutions using the analysis of product melting curves (HMR-analysis) with a set of designed primers. It has been established that Y. pestis strains isolated in the Sarydzhaz autonomous focus of the Tien Shan high-mountain focus belong to the biovar antiqua of the main subspecies, phylogenetic branch 0.ANT5. The phylogenetic relation of Y. pestis strains isolated in 2023 was studied based on genome-wide SNP analysis. Areas of epizootic activity in Eastern Alai have been identified. The data obtained indicate the sustained activation of plague foci in the KR. Areas of the territory of the KR that are promising for paleogenomic research are also discussed.

The isolation of locally adapted rhizobial strains with high symbiotic activity represents an effective strategy for increasing soybean yield under extreme environmental conditions. In this study, seven novel strains were isolated from nodules of soybeans grown in a greenhouse using field soil from the Lower Volga region. Five genomes were assembled into complete circular chromosomes, whereas two strains yielded near-complete chromosomes containing single repeat-mediated junctions. All strains had putative plasmids that were independently validated as circular by long-read mapping and confirmed by the presence of characteristic replication and conjugation-associated genes. Genome sequences of strains were about 11 Mb, and GC contents were 63.1–63.3%. Comparative genome analyses demonstrated that all strains had average nucleotide identity values of 95.4% with Bradyrhizobium japonicum USDA 6^T and 96.3% with Bradyrhizobium barranii 144S4^T, forming a distinct cluster in phylogenetic trees. No significant differences were detected between B. japonicum and B. barranii that would explain the species boundary. Therefore, it is proposed to unite all novel strains into the subspecies Bradyrhizobium japonicum subsp. saratovii subsp. nov., and all other strains of B. japonicum and B. barranii we suggest dividing into four subspecies: Bradyrhizobium japonicum subsp. japonicum subsp. nov., Bradyrhizobium japonicum subsp. barranii comb. nov., Bradyrhizobium japonicum subsp. apii comb. nov., and Bradyrhizobium japonicum subsp. saratovii subsp. nov. The proposed taxonomic framework expands current knowledge of the biodiversity of soybean symbiotic bacteria and contributes to a better understanding of the distribution and the evolution of bacteria Bradyrhizobium spp. in previously unexplored regions.