Objective: to study the seroprevalence of SARS-CoV-2 antibodies (AB) in children in the 2nd year of the COVID-19 pandemic in Russia. Materials and methods: prospective cohort study. The seroprevalence research was conducted among 3670 children aged 1 to 17 y/o from 26 modelling regions of Russia (that have been participating earlier in the five stages of seromonitoring during 2020-2021). The serological testing was carried out in December, 2021. The work was carried out according to a unified methodology set by the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being with the Pasteur Institute of Epidemiology and Microbiology (Saint Petersburg, Russia). The plasma was obtained from 3 ml of venous blood, in which the level of AB to nucleocapsid (NC), and the SARS-CoV-2 receptor-binding domain (RBD) was determined by immunoferment method using reagents for qualitative and quantitative analysis. Results: the analysis of AB seroprevalence to NC and RBD showed the statistically significant increase in the share of seropositivity to RBD in children of all modelling regions (p<0.05). The most seropositive volunteers contained low levels of AB: 31.3-125.6 BAU/ml NC and 22.6-220 BAU/ml RBD. An increase in the level of AB to NC and RBD was accompanied by a decrease in the percentage of seropositive patients. Evaluating the contribution of children to the level of humoral immunity, convalescents (had been ill shortly before the examination), the “anamnesis” (had been ill at previous stages of seromonitoring) and asymptomatic (had been asymptomatically ill) groups were distinguished. The maximum contribution was made by children with asymptomatic cases of COVID-19 in anamnesis: in 82.3% (95% CI 81.1-83.6), of which 76.9% (95% CI 75.5-78.3) AB detected to RBD. The contribution of children of two other groups to the overall level of humoral immunity was 33 times less. Conclusion: statistically significant predominance of AB to RBD above AB to NC and their main contribution to the level of humoral immunity to SARS-CоV-2 (p<0.001).

The aim of the study was to identify differences in the immune response in chronic opisthorchiasis with or without clinical manifestations of hepatobiliary system diseases. A comparison of laboratory parameters of immune system functioning (lymphocyte phenotypes detected by flow cytometry, concentrations of immunoglobulins and cytokines, indicators of nonspecific resistance) in patients with chronic opisthorchiasis (caused by Opisthorchis felineus) lacking clinical manifestations and with manifestations of cholecystitis, cholangitis, pancreatitis, gastritis, gastroduodenitis, confirmed by ultrasound and FGDS. It was found that the immunological parameters of the innate immune response were increased in all patients with chronic opisthorchiasis compared with the control group of apparently healthy subjects, which indicates activated macrophage-phagocytic arm in patients with opisthorchiasis invasion. The indicator of the stimulated HCT test is maximal in chronic opisthorchiasis without hepatobiliary system diseases, in case of comorbidity with such diseases it declines, but remains significantly higher than the values of the control group. This may be due to the exhaustion in the reserve capabilities of bactericidal neutrophil systems in patients with symptoms of damage to the hepatobiliary system due to prolonged inflammation. Indicators of the cellular arm in patients with chronic opisthorchiasis without clinical manifestations of hepatobiliary system diseases demonstrate a decrease in the absolute and relative level of cytotoxic T-lymphocytes. In the group with picture of hepatobiliary system disorders, an even deeper imbalance of indicators is revealed: the relative and absolute level of lymphocytes, the absolute count of T-lymphocytes are reduced, which may indicate about involvement of cellular immunity in the pathogenesis of complications of chronic opisthorchiasis. In all examined patients with chronic opisthorchiasis, the humoral immune response was also activated the total immunoglobulin E was significantly increased; at the same time, in patients with hepatobiliary system lesions, this parameter increases even more and a decrease in B-lymphocytes is detected. In all patients with chronic opisthorchiasis, there is also an increased level of proinflammatory cytokine IL-8, which rises even more in the group with hepatobiliary system diseases. The data obtained indicate the involvement of all arms of the immune response in a prominent inflammatory process when chronic opisthorchiasis is complicated by clinically overt hepatobiliary system diseases: the degree of deviation in the indicators of the innate and adaptive immune response from the norm and from those in uncomplicated opisthorchiasis increases.

Introduction. The incidence of healthcare-associated infections is a major public health problem worldwide, affecting all countries regardless of their economic status. The main agents of these infections are pathogens belonging to the ESKAPE group. The aim of the study was to explore the structure, molecular and antigenic characteristics of the ESKAPE pathogens isolated from oral and anal mucosa of patients of the neonatal intensive care unit (NICU), and to assess their etiological significance in occurrence of healthcare-associated infections. Materials and methods. Samples from a total of 49 children were tested, including 40 newborns patients of NICU at the National Hospital of Pediatrics in Hanoi. Collection and processing of biomaterial (oropharyngeal swabs, rectal swabs) and isolation of bacterial cultures were performed using conventional bacteriological methods. Mass spectrometry was used for identification of isolates. Klebsiella pneumoniae strains were analyzed using the whole-genome sequencing method. Results. The group of gram-positive ESKAPE pathogens identified in oral mucosa was represented by isolates Enterococcus faecium and Staphylococcus aureus. The isolates of the family Enterobacteriaceae included K. pneumoniae, Escherichia coli, Enterobacter cloacae; the group of nonfermenting gram-negative bacteria was represented by Pseudomonas aeruginosa, Acinetobacter baumannii. The structure of ESKAPE pathogens persistent in anal mucosa was characterized by dominance of Enterococcus spp., E. coli, K. pneumoniae and P. aeruginosa bacteria. The whole-genome sequencing of K. pneumoniae isolates revealed 7 clusters and 8 sequence types. ST14 and ST1741 prevailed, accounting for 25%, respectively, of the total number of the studied strains. The molecular serotyping showed that by the O antigen, strains belonged mainly to serotypes O1v1, O1/ O2v2, O5; by the presence of the capsular antigen to serotypes KL2, KL104, KL60. Conclusion. The analysis of the structure of the ESKAPE pathogens isolated from the oral and anal mucosa of patients of NICU at the National Hospital of Pediatrics in Hanoi identified etiologically significant agents of bacterial infections: S. aureus, K. pneumoniae, E. coli, E. cloacae, P. aeruginosa, A. baumannii. The molecular and genetic analysis of K. pneumoniae strains co-circulating in mucous membranes of several patients of the unit revealed their homology, thus confirming healthcare-associated contamination of children with nosocomial strains.

Подведены итоги полугодового исследования микробиоты нижних дыхательных путей пациентов, находящихся на стационарном лечении в пяти моногоспиталях Тюмени и Тюменской области с диагнозом внебольничная пневмония. Установлено, что в микробном пейзаже биопроб пациентов с положительными тестами на РНК SARC-CoV-2 превалировали грамположительные кокки, преимущественно условно-патогенные микроорганизмы рода Streptococcus и грибы рода Candida. При этом бактерии семейства Enterobacteriaceae и неферментирующие грамотрицательные бактерии встречались реже, чем у пациентов без коронавирусной инфекции. В структуре патогенов лидирующее положение занимали бактерии Klebsiella pneumoniae и Acinetobacter spp. Проведенный анализ чувствительности микроорганизмов к антимикробным препаратам показал наиболее высокую резистентность у штаммов Acinetobacter spp., Enterococcus spp., коагулазонегативных Staphylococcus spp. Установлено, что в группе пациентов с внебольничной пневмонией, ассоциированной SARS-CoV-2, шансы встретить штаммы Streptococcus spp. с высокой устойчивостью к антибиотикам в 1,5 раза выше, а с учетом 95% доверительного интервала величина этого показателя колебалась в пределах от 1,1-2,1 раза. Ключевые слова: антибиотико- и фагорезистентность, внебольничная пневмония, SARS-CoV-2, штаммы бактерий, мокрота, промывные воды бронхов, бронхоальвеолярный лаваж.

Summary. Introduction: The urgency of the problem of trichinosis in the Ural Federal District is determined by diversity of animal species, both intermediate and final hosts of Trichinella, and adverse effects of anthropogenic factors on the epizootic situation. The purpose of the study was to generalize and analyze long-term monitoring data on the species structure of Trichinella hosts, the level of infestation, and the intensity of invasion in wild and domestic mammals in various invasion reservoirs. We analyzed information about complex ecological interactions in the foci, environmental and geographical features and their role in the pathogen circulation. Our findings can serve as the basis for epizootiological monitoring in constituent entities of the Ural Federal District and elaboration of preventive measures. Materials and methods: We reviewed literary sources on the topic published since the late 1960s, analyzed information bulletins of the Federal Center for State Sanitary and Epidemiological Surveillance and the Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing (Rospotrebnadzor) reporting trichinellosis rates and preventive actions as well as publications of the same body on epizootiological characteristics of trichinosis, and information issued by regional offices of veterinary medicine and the Federal Service for Veterinary and Phytosanitary Surveillance (Rosselkhoznadzor). The analytical method and the comparative historical research method were applied. Results: We established the relevance of the problem of trichinosis in the Ural Federal District. The natural reservoir of Trichinella in the area is provided by a detachment of carnivorous mammals (Carnivora) of the bear (Ursidae), canine (Canidae), mustel (Mustelidae), and feline (Felidae) families. Natural reservoirs with varying degrees of extensiveness and intensity of invasion in wild animals determine danger of transition of invasion into the synanthropic environment with the formation of local foci. The presence of foci at risk of infection depends on the frequency of contact with the invasive onset. In view of local synanthropic and natural diffuse foci found in different parts of the Ural Federal District, adverse anthropogenic impacts, and complicated socio-economic problems, the need for epidemiological monitoring (both epidemiological and epizootiological observations) of biocenotic components of the territories acquires special importance and requires constant attention of responsible governmental services to the epizootic and epidemiological situation.