[Evaluation of the dynamics of detection of viable SARS-CoV-2 (Coronaviridae: Betacoronavirus: Sarbecovirus) in biological samples obtained from patients with COVID-19 in a health care setting, as one of the indicators of the infectivity of the virus]

INTRODUCTION

The study of the mechanisms of transmission of the SARS-CoV-2 virus is the basis for building a strategy for anti-epidemic measures in the context of the COVID-19 pandemic. Understanding in what time frame a patient can spread SARS-CoV-2 is just as important as knowing the transmission mechanisms themselves. This information is necessary to develop effective measures to prevent infection by breaking the chains of transmission of the virus. The aim of the work is to identify the infectious SARS-CoV-2 virus in patient samples in the course of the disease and to determine the duration of virus shedding in patients with varying severity of COVID-19.

MATERIALS AND METHODS

In patients included in the study, biomaterial (nasopharyngeal swabs) was subjected to analysis by quantitative RT-PCR and virological determination of infectivity of the virus.

RESULTS

We have determined the timeframe of maintaining the infectivity of the virus in patients hospitalized with severe and moderate COVID-19. Based on the results of the study, we made an analysis of the relationship between the amount of detected SARS-CoV-2 RNA and the infectivity of the virus in vitro in patients with COVID-19. The median time of the infectious virus shedding was 8 days. In addition, a comparative analysis of different protocols for the detection of the viral RNA in relation to the identification of the infectious virus was carried out.

CONCLUSION

The obtained data make it possible to assess the dynamics of SARS-CoV-2 detection and viral load in patients with COVID-19 and indicate the significance of these parameters for the subsequent spread of the virus and the organization of preventive measures.

Experience of tocilizumab in hospital patients with moderate COVID-19

Severe form of COVID 19 has been linked to the phenomenon of dysregulated inflammation with excessive cytokine release and elevated interleukin 6 (IL6) levels. Suppressive agents enabling specific inhibition of cytokines, notably monoclonal antibodies to IL6 and its receptors, have been applied as a rescue therapy in COVID 19 despite the underexplored clinical scope for these biologic medications. This study aimed to evaluate the clinical utility of IL6 receptor antagonist tocilizumab in moderate symptomatic COVID 19 prone to aggravation. The retrospective cohort study enrolled two groups of hospitalized patients (a total of n = 72) diagnosed with moderate COVID-19. The main group received a single 400 mg dose of tocilizumab (TCZ) on top of standard therapy. The comparative analysis included statistical evaluation for a number of clinical and laboratory parameters at reference time points and disease outcomes with regard to treatment strategy. Overall, TCZ administration provided no advantages in terms of oxygen supplementation status, disease progression, or survival. Lethal cases constituted 19.2% (10 pts) and 5% (1 pt) in TCZ and comparison groups, respectively. The results indicate that administration of monoclonal antibody drugs in hospital patients with COVID-19 must follow differential schemes with regard to the disease severity and comorbidities, as well as proper commencement schedules.

Properties of RBD specific IgG from COVID-19 patients and Sputnik V vaccinated individuals

SARS-CoV-2 specific antibody response is a generally accepted measure of postinfection and vaccination-induced immunity assessment. The dynamics of avidity maturation and neutralizing activity of virus-specific immunoglobulins G during the SARS-CoV-2–associated coronavirus infection was studied in cohorts of vaccinated volunteers and COVID-19 patients. 4–6 months after vaccination, neutralization activity was low compared to hospitalized patients (medians 57.4% vs 86.4%). On the opposite, the avidity indices in vaccinated volunteers were significantly higher (median 76.7%) than among hospitalized patients (median 61.4%). During the acute phase of the disease (14–16 days PI), post-vaccination patients have also higher avidity indices than primary patients (medians 43.5% vs 20.4%). Our results suggest that in long-term perspective antibody affinity maturation rate is higher after vaccination than after a natural infection. We demonstrated that Sputnik V vaccination leads to formation of high-avidity IgG, which persists for at least 6 months of observation. These results also indicate the presence of protective efficacy markers for at least 4–6 months after the vaccination or a previous illness and gives grounds for the half-year time period chosen for booster immunization with Sputnik V in Russia.

Assessment of COVID-19 clinical course in patients vaccinated with Spitnik V, SARS-CoV-2 S protein RBD domain variation and serum virus neutralizing activity

The COVID-19-associated mortality remains high. Studying the features of the COVID-19 course in vaccinated patients, who have got ill on different dates after vaccination, compared to unvaccinated individuals is relevant. The study was aimed to assess clinical and immunological features of the COVID-19 course, as well as to assess humoral immunity (virus neutralizing activity, VNA) and SARS-CoV-2 S protein RBD domain variation in the groups of patients, previously vaccinated with Sputnik V, and unvaccinated patients. A total of 251 patients with confirmed diagnosis of COVID-19 were enrolled, of them 116 individuals were previously vaccinated with one or two Sputnik V vaccine components, and 135 patients were not vaccinated (comparison group). Individuals over 50 years of age prevailed (82.8%). The patients, who received two vaccine components, had mild to moderate COVID-19 (92.1%). In the group of unvaccinated patients, 11 individuals received treatment in the ICU, 10 of them died. The viral load was significantly lower in vaccinated patients. Mutations of SARS-CoV-2, such as S477N, S477N+A522S, E484K and E484K+S494P, were identified both in vaccinated and unvaccinated patients. Assessment of the neutralizing activity of sera revealed no significant differences in VNA against different variants of SARS-CoV-2 mutations. The data obtained demonstrate that the lack of vaccination is an aggravating factor and is capable of increasing the risk of severe course and death in patients with COVID-19.

COVID-19: etiology, clinical picture, treatment

Whereas the XX century marked the history of acute respiratory disease investigation as a period for generating in-depth system of combating influenza viruses (Articulavirales: Orthomyxoviridae, Alpha-/Betainfluenzavirus) (based on environmental and virological monitoring of influenza A virus in its natural reservoir — aquatic and semi-aquatic birds — to supervising epidemic influenza), a similar system is necessary to build up in the XXI century with regard to especially dangerous betacoronaviruses (Nidovirales: Coronaviridae, Betacoronavirus): Severe acute respiratory syndrome-related coronavirus (SARS-CoV) (subgenus Sarbecovirus), Severe acute respiratory syndrome-related coronavirus 2 (SARSCoV-2) (Sarbecovirus), Middle East respiratory syndrome-related coronavirus (MERS-CoV) (Merbecovirus). This became particularly evident after pandemic potential has been revealed in 2020 by the SARS-CoV-2. This review provides an insight into the historic timeline of discovering this virus, its current taxonomy, ecology, virion morphology, life cycle, molecular biology, pathogenesis and clinical picture of the etiologically related COVID-19 (Coronavirus disease 2019) as well as data available in the scientific literature on the anti-SARS-CoV-2-effectiveness of passive immunotherapy and most debated drugs used to treat COVID-19: Chloroquine, Hydroxychloroquine, Nitazoxanide, Ivermectin, Lopinavir and Ritonavir, Camostat mesilate, Remdesivir, Ribavirin, Tocilizumab, Anakinra, corticosteroids, and type I interferons. The pathogenesis of SARS-CoV-2 infection implicates decreased efficacy of artificial respiration, which, in this case might be replaced by more efficient extracorporeal membrane blood oxygenation supplemented with nitrogen oxide and/or Heliox inhalations.

[Features of nutrition of elderly patients with removable dental orthopedic constructions]

RESEARCH OBJECTIVE

studying of features of nutrition in elderly patients with removable stomatologic orthopedic constructions. 1388 patients aged from 60 up to 75 years which addressed in a city dental out-patient department were examined. Patients were divided into three groups: group 1 - the persons having only fixed stomatologic orthopedic constructions (n=419); group 2 - the persons having at least one partially removable stomatologic orthopedic construction and not having full-removable orthopedic constructions (n=512); group 3 - the persons having at least one full-removable stomatologic orthopedic construction (n=457). Patients were interviewed about nutrition features (frequency of consumption). Anthropometric researches were conducted. There were 2.2 and 1.3 fold more persons in group 3 with a concomitant increase in waist circumference and waist-hip ratio compared to groups 1 and 2 (p=0.0013). Persons from group 3 consumed meat significantly less often than patients in groups 1 and 2. A similar trend was observed for meat products, vegetables and fruits (p<0.05). Compared to patients in groups 1 and 2, patients from group 3 more often consumed cereals, potatoes, rice, pasta, as well as sauces, mayonnaises, margarines. All examined elderly patients rarely consumed fish and seafood (76.0-89.9% persons consumed once a month and less often).

[THE PATHOGENIC POTENTIAL OF MORAXELLA CATARRHALIS AND STAPHYLOCOCCUS EPIDERMIDIS UNDER INFLAMMATORY PROCESSES OF UPPER RESPIRATORY TRACTS]

The frequent isolation from biological material of Moraxella catarrhalis under bronchitis and pneumonia and Staphilococcus epidermidis under rhinitis and sinusitis requires profound investigation offactors ofpathogenicity ofthe mentioned microorganisms. The genetic and phenotypic markers of virulence of strains M. catarrhalis and S. epidermidis are examined. Their etiologic role in development of infection processes of respiratory tract and middle ear is determined The most of M catarrhalis strains isolated under bronchitis and pneumonia have gene mcaP responsiblefor production ofprotein McaP that provides adhesion to epithelium cell of host and lipolitic activity of bacteria. The strains isolated from patients with pneumonia had the most adhesive activity. The cluster of genes ICA with leading role of gene icaA is responsible for for availability offactors of intercellular adhesion in Staphilococci strains. In the clinical samples from patients with sinusitis this gene is detected 5 times more frequently than from healthy individuals. In phenotypic tests, expression of gene icaA in S. epidermidis isolated from patients is three times higher than in strains isolated from healthy individuals. To establish etiologic role of M. catarrhalis and S. epidermidis and to develop tactic of therapy of patients with bronchitis, pneumonia and sinusitis complex approach is needed, including detection of genetic and phenotypic markers of virulence in isolated microorganisms.

[Antagonistic activity of lactobacilli of the colon]

AIM

Study of antagonistic activity of lactobacilli of the colon against members of its autochthonous bacterial flora and agents of some acute infectious and chronic diseases of the gastrointestinal tract.

MATERIALS AND METHODS

Antagonistic activity of 19 lactobacilli cultures against 28 cultures of bacteria belonging to various groups and fungi was evaluated within the framework of specially developed two-stage cultivation technique in the conditions of a combined system. The results of the study were evaluated according to a semi-quantitative scale that allows to put one or the other value of the zone of growth delay of the studied strain culture in compliance with the one or the other (low, moderate, high) level of antagonistic activity of the lactobacillus culture.

RESULTS

Lactobacilli of the colon showed selective antagonistic activity against pathogenic enterobacteriae: pronounced against Salmonella enterica Serovar Enteritidis, Shigella flexneri 2b, Yersinia spp., and trace against Salmonella enterica Serovar Typhimurium. The level of antagonistic activity of lactobacilli against a wide range of members of autochthonous bacterial flora varied in a wide range, without revealing connection neither to its belonging to species, nor to its population level, nor to the belonging to group of the antagonistic effect objects. On the other hand a connection was traced with beloriging to a certain microbiota: being quite active against members of its own microbiota, lactobacilli often showed significantly lower level of antagonistic activity against cultures with the same species name isolated from other microbiota.

CONCLUSION

In light of the results obtained, level of lactobacilli population may hardly be viewed as the only criteria of their full participation in the process of stabilizing microecological welfare of the colon, that allows to make a complete representation of the level of dysbiotic disorder in the mentioned biotope. With in the framework of rational bacteriological diagnostics of the level of dysbiotic disorders in the colon, evaluation of population level of lactobacilli should be evaluated along with the degree of their antagonistic activity against other components of the same microbiota.

[Features of cytokine levels in serum of patients with tick-borne borreliosis with different clinical signs]

AIM

To assess levels of several cytokines in blood of patients with tick-borne borreliosis (Lyme disease) with different clinical variants of the disease.

MATERIALS AND METHODS

Study of complex of proinflammatory cytokines (IFNalpha, IL-1beta, IFNgamma, IL-2, IL-4, IL-8) during course of the disease was performed by solid-phase ELISA using domestic diagnostic kits (Scientific Manufacturing Organization "Proteinovyi Contur", "Cytokine" Ltd., Saint Petersburg). Levels of TNFalpha was determined by ELISA using commercial kits "Boehringer Manheim" (Austria).

RESULTS

Performed comparative clinico-laboratory analysis demonstrated increased levels of LL-2, IL-4, and IL-8 in patients during acute phase of tick-borne borreliosis that could point to host's response on bacterial infection. It should be noted that in patients with arthritis levels of LL-4 and IL-2 remained high during recovery phase that probably determined by possible persistence of Borrelia burgdorferi.

CONCLUSION

Further research of cytokines during Lyme borreliosis could have important diagnostic and prognostic value.

[To the differential diagnosis of arthritis of pseudotuberculous and chlamydial etiology]

AIM

to define main differential diagnostic criteria for arthritides of chlamydial and pseudotuberculous etiology and to improve patient examination tactics.

SUBJECTS AND METHODS

Forty-six patients with pseudotuberculosis and 41 patients with chronic urogenital chlamydial infection with articular involvement were examined. A bacteriological method of polymerase chain reaction (PCR), agglutination test, enzyme immunoassay (EIA) (IgA, IgG, IgM), indirect hemagglutination (IHA) test were used to diagnose pseudotuberculosis. Diagnostic techniques for chlamydiasis involved cultural, direct immunofluorescence (DIF), real-time PCR, and EIA (IgM, IgG, IgA).

RESULTS

Patients with pseudotuberculosis developed polyarthritis and oligoarthritis in 56 and 39%, respectively. The development of arthritides was accompanied by fever in 89%, exanthema in 57%, gastrointestinal lesion in 56%, hepatomegalia in 78%. The pseudotuberculous etiology of the disease was confirmed by the agglutination test in 71% of the patients and by IHA in 7%. EIA revealed IgG in 78% of the patients, IgA in 11%, and IgM in 29%. PCR of synovial fluid (SF), synovial shell, and other biological substrates revealed Yersinia pseudotuberculosis DNA in 43%. Chlamydiasis and polyarthritis developed in 71 and 19%, respectively. The diagnosis of chlamydiasis was verified by EIA detection of IgG and IgA in 76 and 27% of cases, respectively. DIF, PCR, and culture studies of urethral scrapes found Chlamydia in 9, 32, and 29% of cases, respectively. Examination of SF and synovial shells revealed Chlamydia trachomatis in 24% of the patients and culture studies detected the pathogen in 21%.

CONCLUSION

Asymmetrical polyarthritides mainly involving the knee joints are the most common arthritides of pseudotuberculous etiology. EIA detection of serum IgG and IgA and PCR study of SF are optimal diagnostic tools. Artritides of chlamydial etiology are asymmetrical oligoarthritides predominantly involving the knee and ankle joints. Examination of urethral and cervical canal scrapes, SF by culture and PCR studies and that of serum IgA and IgG by EIA are optimal diagnostic tests.

[A comparative evaluation of different immunological reactions in the diagnosis of pseudotuberculosis]

To study humoral response in patients with the generalized form of pseudotuberculosis, the agglutination test, the passive hemagglutination test and the complement fixation test with antigen obtained from "Virion" (Switzerland) were used. The study of the dynamics of antibody formation to outer membrane proteins (OMP) and Yersinia pseudotuberculosis (pYV+ and pYV-) lipopolysaccharide (LPS) revealed that the synthesis of antibodies to OMP, controlled by inv gene, exceeded the synthesis of antibodies to LPS at all periods of the disease, which determined the necessity of further study of the role of OMP in pathogenesis and in the formation of humoral response. On the basis of the study of the occurrence of antigens a high diagnostic effectiveness the enzyme immunoassay for the detection of Y. pseudotuberculosis antigens, mainly at the first stage of the disease, was noted.