Vol 101, No 3 (2024)

Introduction. Salmonella Kentucky sequence type ST198 is one of the epidemiologically significant non-typhoidal Salmonella clones worldwide and is characterized by the presence of highly resistant strains and the ability to adapt to different animal hosts and environmental conditions.

The aim of this study was to analyze S. Kentucky strains isolated from various sources in Russia in terms of their phylogenetic position within the global diversity of the pathogen and their genetic characteristics.

Materials and methods. We examined 55 strains of S. Kentucky by whole-genome sequencing, which were isolated from 2010 to 2022 from various sources (clinical strains, food, as well as from farm animals, feed and environmental samples). Whole genome sequencing was performed using Illumina platforms. Phylogenetic analysis based on nucleotide variation analysis included an additional 390 S. Kentucky strains.

Results. Most of the Russian strains (n = 50) belonged to the ST198 sequence type, four strains were ST314 and one strain was ST152. Of the 50 Russian sequence-type ST198 strains, 44 belonged to the international monophyletic MDR lineage S. Kentucky ST198, and belonged to four separate sublineages, six strains occupying a basal position in relation to the MDR lineage. A total of 320 genes and mutations responsible for resistance to antimicrobial agents were identified. The most common were point mutations in the QRDR region. In most cases, Russian strains were characterized by the presence of variants of the SGI1-K genomic island. Moreover, the putative structure of SGI1 was correlated with the phylogenetic clustering of S. Kentucky sublineages.

Conclusions. The results of the study made it possible to assess the population structure of Russian S. Kentucky ST198 strains on a global scale and determine the genetic determinants of antibiotic resistance, including the structure of the SGI1 genomic island.

Introduction. The traditional surveillance system for influenza and ARVI provides a general description of epidemics, but does not provide information on the age-related characteristics of the etiology and clinical peculiarities of severe acute respiratory diseases (SARI) in hospitalized patients.

Aim. To monitor the etiology of SARI in hospitalized children and adults, assessing the impact of the COVID-19 pandemic on this process.

Materials and methods. Standardized clinical and laboratory monitoring of SARI among 18,458 hospitalized patients was carried out in hospitals in three cities of Russia with weekly PCR detection of 11 types of pathogens.

Results. According to the investigation of hospitalized patients with SARI for the period from 2018 to 2023, the viral etiology of respiratory diseases was deciphered in 58.3% of cases. Weekly monitoring showed a change in the etiological mosaic of SARI pathogens during the SARS-CoV-2 pandemic with a sharp decrease in the frequency of detection of influenza and respiratory syncytial virus (RSV) during the 2020–2021 season against the background of a significant increase of metapneumovirus and rhinovirus infections in children. During the 2022-2023 season an increase in the proportion of RSV infection in children under 6 years of age (up to 36.2%) was noted against the background of a significant decrease in the frequency of SARS-CoV-2. In the intensive care units (ICU), RSV infection was most often in children during the post-pandemic period (up to 30.1–53.6% of positive cases, p < 0.001); in adults, SARS-CoV-2 was mostly detected (76,5–100% of cases, p < 0.001).

Conclusion. Hospital surveillance data significantly complements the epidemiological information obtained in the traditional surveillance system. Monitoring of infections has shown a continuously changing etiological infrastructure of SARI, with the disappearance of influenza and RSV during the COVID-19 pandemic and their return to circulation in the post-pandemic period.

Introduction. Enteroviruses (EV) are characterized by: species and type diversity, polymorphism of clinical manifestations, a tendency to epidemic spread, and are often the cause of disease outbreaks, which determines the relevance of monitoring EV strains in various clinical forms of infection, including in conditions of anti-epidemic measures.

The aim of the study: to characterize the prevalence and diversity of non-polio enteroviruses (NPEV) types in children with acute intestinal infection (AII) in the period 2018–2023, including the COVID-19 pandemic.

Materials and methods. The RT-PCR method was used to study 7302 samples of feces from children hospitalized with a diagnosis of AII in the infectious diseases hospital of Nizhny Novgorod. Genotyping of EV strains was carried out using fragment Sanger sequencing of the genome region encoding capsid protein 1 (VP1) and the online resource BLAST.

Results. EVs were found in 5.0 ± 0.3% (1.7–7.8%), both in mono- and mixed infections with other enteric viruses. The long-term dynamics of the frequency of EV detection and the incidence of EV infection in children in the Nizhny Novgorod region was characterized by a sharp decrease in indicators in 2020 against the backdrop of the introduction of anti-epidemic measures. When genotyping 299 strains, 41 types of NPEV of 4 species were identified. The spectrum included the main pathogens of exanthema and neuroinfections and rare types found in “minor” or intestinal forms of infection. During the study period, a redistribution of NPEV species was established. Before the pandemic, the ratio of Enterovirus A : Enterovirus B : Enterovirus C species was as follows — 41.0 : 46.7 : 12.3%; during the 2020 pandemic season the ratio was 0.0 : 37.5 : 62.5%; after the lifting of restrictive measures — 47 : 29 : 23%, which may be due to the different effectiveness of the restrictive measures on the mechanisms of transmission of EVs of different types.

Conclusion. The genetic diversity of NPEVs detected in children with AII complements information on the typical composition of the territorial enterovirus population. In children with AII, when the airborne transmission of SARS-CoV-2 was blocked, there was a decrease in the frequency of detection of viruses of the Enterovirus B type, the absence of detection of Enterovirus A and the constant presence of Enterovirus C.

Introduction. Based on data on the role of blood erythrocytes in the development and implementation of the vaccine and infectious processes in plague, it was of interest to evaluate changes in erythrocyte surface architecture from the position of searching for informative criteria for the preclinical evaluation of anti-plague vaccines.

Aim — using atomic force microscopy to characterize the state of the blood erythrocyte membrane of guinea pigs in response to subcutaneous administration of the vaccine strain Yersinia pestis EV NIIEG and its isogenic derivatives.

Materials and methods. For immunization of animals strain Y. pestis EV NIIEG (pYT⁺, pYV⁺, pYP⁺) and its isogenic derivatives Y. pestis KM216 (pYT^–, pYV^–, pYP⁺), Y. pestis KM217 (pYT^–, pYV⁺, pYP^–), Y. pestis KM218 (pYT^–, pYV^–, pYP^–) were used. Analysis of the erythrocyte membrane was carried out using a Solver P47-PRO scanning probe microscope (NT-MDT, Russia).

Results. The most pronounced changes in the surface architectonics of the membrane of guinea pig erythrocytes were established during the first three days of the formation of the immune response to the Y. pestis EV strain NIIEG and its isogenic variant Y. pestis KM217, in the genome of which the pYV plasmid is preserved, administered at a dose of 5 × 10⁸ CFU. A significant increase (p < 0.05) in the proportion of transformed cell forms (43.67 ± 3.63% and 37.83 ± 7.03% versus 4.08 ± 0.86% in the control group), root mean square roughness (319 ± 8 nm and 312 ± 7 nm versus 70 ± 6 nm in the control group), Young's modulus (125.73 ± 4.48 kPa and 113.8 ± 5.41 kPa versus 53.03 ± 1.47 kPa in the control group). By the 21^st day, the value of these indicators decreased by an average of 2.7, 2.0 and 1.5 times, respectively, indicating restoration of the erythrocyte membrane.

Conclusion. The dependence of the changes in the erythrocyte membrane and the rate of their restoration on the plasmid composition of Y. pestis strains has been established. The data obtained contribute to the understanding of the processes of interaction of Y. pestis with the erythrocyte membrane and can be used as additional characteristics in the development of new criteria for preclinical evaluation of plague candidate vaccines.

The aim of the review is to give a brief description of the biodiversity and structure of the hospital environment microbiome based on molecular genetic research methods.

Until a certain time, studies of the hospital environment microbiota for the purposes of epidemiological surveillance and control of healthcare-associated infections (HAIs) were based on routine microbiological identification of clinically relevant bacterial taxa. Discovery of DNA, the development of sequencing technologies, PCR and cloning techniques enabled the investigation of microbial communities using cultivation-independent, DNA and RNA-based approaches. At the current level of knowledge, the hospital environment can be considered as a superorganism with its own microbiome. Multiomic technologies, including meta-transcriptomic, meta-proteomic and metabolomic approaches, provide detailed information about microbial activity in the environment. Now it has been established that there is a stable core of the hospital microbiome where the vast majority of microorganisms are necessary for the functioning of the hospital ecosystem and are not classified as human pathogens. The hospital microbiome has a homogeneous structure composed by a massive dominance of a few taxa and microbial network with low connectivity forming a clustered topology. A keystone species is a taxon whose importance for maintaining community structure is relatively higher than others and its identification is of paramount importance. Due to the lack of knowledge of the hospital environment microbiome by molecular genetic technologies, there is no single shared point of view on the microbial diversity in different healthcare facilities. But there is no doubt that molecular genetic technologies will shed light on the evolution of hospital strains and determine which indicators are the most informative for monitoring and prognosis of HAIs.

Monoclonal antibodies are widely used in all fields of biology and medicine. The emergence and development of the technology for their production revolutionized immunology and allowed the creation of not only new diagnostic methods, but also many effective drugs. The purpose of our review is to analyze and summarize relevant data concerning the technology of obtaining monoclonal antibodies. We have analyzed information from 70 modern literary sources devoted to various methods of obtaining them. In this review, we tried to cover the entire range of methods used to obtain monoclonal antibodies today.