Vol 98, No 4 (2021)

Cover Page

Full Issue


Experience of international cooperation in developing epidemic control measures during COVID-19 spread in the Republic of Moldova

Popova A.Y., Ruzhentsova T.A., Krasovskaya T.Y., Аlbul K.V., Beril N.V., Paladi I.Z., Garbuzov A.A., Khavkina D.A., Chuhliaev P.V.


The purpose of the study — to identify the factors contributing to the spread of the novel coronavirus infection within the territory of the Republic of Moldova and to develop measures aimed at their elimination.

Materials and methods. In May 2020, experts of Rospotrebnadzor (the Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing), together with leading employees of institutions participating in planning and implementing measures aimed at prevention of COVID-19 spread, conducted a detailed analysis of epidemic control and curative measures in 10 healthcare organizations in the Republic of Moldova. They assessed the effectiveness of the undertaken actions in in-patient facilities, in laboratories, and in the country in general.

Results. The existing approaches to treatment of patients with COVID-19 and to laboratory diagnostics were in line with the common practices; the adequacy of measures was evidenced by the hospital bed capacity and the stock of artificial lung ventilation machines. In the meantime, the experts came across the factors that obviously contributed to the infection spread. Their elimination could intercept some paths of infection and improve the situation.

Conclusion. The analysis of the current measures and their results is important for planning and implementing actions aimed at improvement of the epidemic situation in different regions. The collaborative efforts helped slow down the outbreak in the Bender psychoneurological residential facility; outbreaks were prevented in other limited-access institutions; the incidence among healthcare workers decreased; the daily number of new COVID-19 cases decreased to 0–5 during the summer months in the Dniestrian Moldovan Republic. Presently, there is a clear picture of approaches that should be taken to decrease the incidence. Most likely, the experience obtained in the fight against the novel coronavirus infection will be of great use in future if any new variants of viruses emerge.

Journal of microbiology, epidemiology and immunobiology. 2021;98(4):373-382
pages 373-382 views

Prevalence of ARVI, influenza, and COVID-19 pathogens in individuals without symptoms of respiratory infection

Yatsyshina S.B., Mamoshina M.V., Elkina M.A., Sharukho G.V., Raspopova Y.I., Folmer А.Y., Agapov K.A., Vladimirov I.M., Zubareva O.V., Novikova I.S., Bondareva O.B., Gil V.A., Kozlovskikh D.N., Romanov S.V., Dikonskaya O.V., Ponomareva A.V., Chistyakova I.V., Kochneva N.I., Yurovskikh A.I., Kadnikova E.P., Kilyachina A.S., Luchinina S.V., Kosareva R.R., Chirkova G.G., Valeullina N.N., Lebedeva L.A., Detkovskaya T.N., Abbasova E.I., Romanova O.B., Pyatyrova E.V., Akimkin V.G.


Introduction. SARS-CoV-2 can be transmitted by infected people without or with mild symptoms of acute respira-tory infection (ARI). Monitoring based on nucleic acid amplification techniques is used to measure the prevalence of ARI pathogens and to assess the effectiveness of preventive measures.

The aim is to measure the prevalence of pathogens causing ARIs of viral etiology, influenza, and COVID-19 among individuals without ARI symptoms throughout age groups, to trace changes in the epidemic situation by weekly monitoring pathogens during the inter-epidemic period and at the beginning of a typical ARI epidemic season, to assess the effectiveness of medical masks for prevention of the above infections.

Materials and methods. A total of 14,119 people (including 4,582 children) without ARI symptoms went through examination, including questionnaire surveys, in 26 regions of Russia from August to October 2020. Nasopharyn-geal and oropharyngeal swabs were tested by using AmpliSens ARVI-screen-FL, AmpliSens Influenza virus A/B-FL, and AmpliSens Cov-Bat-FL reagent kits (The Central Research Institute of Epidemiology of Rospotrebnadzor, Moscow).

Results. 11.1% of the tested samples showed positive results; the rhinovirus prevailed (7.32%), while SARS-CoV-2 was detected in 1.66%. In autumn, the proportion of SARS-CoV-2 infected cases increased from 0.49% to 4.02% (p < 0.001). The SARS-CoV-2 RNA concentration was up to 1010 copies/mL.

Conclusions. Differences in the prevalence of SARS-CoV-2 and rhinovirus among the age groups and over time were found and analyzed. Using of medical masks reduced the risk of infection with respiratory viruses and with SARS-CoV-2 by 51% and 34%, respectively. In case of prolonged exposure to a COVID-19 patient, healthy people must use a respirator for more effective protection. The individuals whose work was associated with a high level of social contacts were infected more rarely than other individuals in the same age group (p = 0.001); this fact supports the importance of anti-epidemic measures and commitment to their adherence by people whose profession entails frequent social contacts.

Journal of microbiology, epidemiology and immunobiology. 2021;98(4):383-396
pages 383-396 views

Metabolome and exposome profiling of the biospecimens from COVID-19 patients in India

Aggarwal S., Parihari S., Banerjee A., Roy J., Banerjee N., Bankar R., Kumar S., Choudhury M., Shah R., Bhojak K., Palanivel V., Salkar A., Agrawal S., Shrivastav O., Shastri J., Srivastava S.


Introduction. COVID-19 has become a global impediment by bringing everything to a halt starting from January 2020. India underwent the lockdown starting from 22nd March 2020 with the sudden spike in the number of COVID-19 patients in major cities and states. This study focused on how metabolites play a crucial role in SARSCoV-2 prognosis.

Materials and methods. Metabolome profiling of 106 plasma samples and 24 swab samples from symptomatic patients in the Indian population of the Mumbai region was done. COVID-19 positive samples were further segregated under the non-severe COVID-19 and severe COVID-19 patient cohort for both plasma and swab.

Results. After analyzing the raw files, total 7,949 and 12,871 metabolites in plasma and swab were found. 11 and 35 significantly altered metabolites were found in COVID-19 positive compared to COVID-19 negative plasma and swab samples, respectively. Also, 9 and 23 significantly altered metabolites were found in severe COVID-19 positive to non-severe COVID-19 positive plasma and swab samples, respectively. The majorly affected pathways in COVID-19 patients were found to be the amino acid metabolism pathway, sphingosine metabolism pathway, and bile salt metabolism pathway.

Conclusion. This study facilitates identification of potential metabolite-based biomarker candidates for rapid diagnosis and prognosis for clinical applications.

Journal of microbiology, epidemiology and immunobiology. 2021;98(4):397-415
pages 397-415 views

Microbial synthesis and evaluation of bactericidal properties of cadmium sulfide nanoparticles

Zhuravliova O.A., Voeikova T.A., Kuligin V.S., Debabov V.G.


Introduction. The productivity of microbial synthesis of stable nanoparticles is determined by the growth stage of the populations of bacterial cultures used to obtain nanostructures. The study of the biocidal activity of biogenic nanoparticles of cadmium sulfide (NPsCdS), comparable in properties with nanomaterials obtained by physicochemical methods, is promising.

The aim of this work was to evaluate the effect of the cell growth phase of the bacterial strains Bacillus subtilis 168 and Shewanella oneidensis MR-1 on the efficiency of biosynthesis of NPsCdS and to study their bactericidal properties against a number of gram-positive and gram-negative strains of microorganisms.

Material and methods. Nanoparticles were obtained by introducing Na2S and CdCl2 salts to a final concentration of 2 mM : 2 mM in liquid bacterial cultures with cells in different phases of growth. The efficiency of NPsCdS biosynthesis was evaluated by the optical density of aqueous nanoparticles solutions. The bactericidal properties of NPsCdS were determined by the diameter of zone of inhibition growth of gram-positive bacteria B. subtilis 168, B. amyloliquefaciens, Streptococcus salivarius, Rhodococcus rhodochrous and gram-negative S. oneidensis MR-1, Escherichia coli K-12, Pseudomonas putida.

Results. It was found that the use of cells in the stationary phase of growth (18–24 hours) contributes to obtaining the maximum amount of NPsCdS corresponding to concentrations of 1.0–1.2 mg/ml. The high antimicrobial activity of NPsCdS was shown against gram-positive microorganisms, among gram-negative bacteria, P. putida strain showed insignificant sensitivity.

Discussion. The experimental results expand scientific data about the effect of the phase of bacterial growth cycle on biosynthesis of nanoparticles. The stationary phase of growth of B. subtilis 168, S. oneidensis MR-1 is optimal for obtaining of NPsCdS. For the first time, the cytotoxicity of NPsCdS/Shewanella against bacteria of various taxonomic groups was demonstrated.

Conclusion. An effective method for obtaining extracellular NPsCdS using bacteria B. subtilis 168, S. oneidensis MR-1 in the stationary phase of growth has been developed. The biocidal activity of biogenic NPsCdS was shown, which allows to consider them as a new class of antimicrobial agents.

Journal of microbiology, epidemiology and immunobiology. 2021;98(4):416-425
pages 416-425 views

Formation in vitro of colistin resistance in carbapenem-resistant Gram-negative bacteria and its biological cost

Tapalski D.V., Petrovskaya T.A., Kozlov A.E.


Introduction. The spread of resistance to carbapenems among gram-negative bacteria have led to an increase in the consumption of polymyxins and the emergence of certain strains resistant to them. Polymyxin resistance is mainly associated with mutations in chromosomal genes. The development of mutational resistance to antibiotics can lead to a decrease in the viability of bacteria; which is manifested by an increase in the duration of the cell cycle; a decrease in virulence and competitive fitness.

The purpose of the study was to assess in vitro the intensity of the formation of colistin resistance in carbapenemresistant clinical isolates of gram-negative bacteria; the stability of the formed emerged resistance and its biological cost.

Materials and methods. For 46 strains of Klebsiella pneumoniae; 77 strains of Pseudomonas aeruginosa and 42 strains of Acinetobacter baumannii; real time polymerase chain reaction (PCR) was used to detect the genes of carbapenemases; the minimum inhibitory concentrations (MIC) of meropenem and colistin were determined by broth microdilution method. The selection of resistant subpopulations on Muller–Hinton agar with the addition of 16 mg/l colistin was carried out. For colistin-resistant mutants and their isogenic sensitive strains; the kinetic parameters of growth in broth culture were determined. Incubation and result recording were performed on an Infinite M200 microplate reader for 18.5 hours at 35°C with measurement of light scatter in the wells every 15 minutes.

Results. The production of carbapenemases MBL VIM in P. aeruginosa; MBL NDM; KPC and OXA-48 in K. pneumoniae; OXA-23 and OXA-40 in A. baumannii was observed. All strains were sensitive to colistin (MIC varied from 0.062 to 2 mg/l). The colony growth on a selective medium with16 mg/l colistin was observed for 97.8% of K. pneumoniae strains; 16.9% of P. aeruginosa strains; and 61.9% of A. baumannii strains. The mutational nature of colistin resistance was confirmed for 21.7% of K. pneumoniae strains. For colistin-resistant mutants of K. pneumoniae; a significant increase in the duration of the lag phase (Tlag) was observed: 225.6 ± 7.037 min in the wild-type susceptible strains and 245.5 ± 8.726 in resistant mutants; p = 0.037. The indicators of the doubling time of the number of microbial cells in the exponential growth phase (Tdoubling) and the area under the bacterial growth curve did not differ significantly.

Conclusion. A high frequency of formation of colistin resistance in vitro in carbapenemase-producing strains of K. pneumoniae was observed. The absence of significant changes in the kinetics of microbial growth in resistant strains makes it possible to predict the further spread of mutational resistance to colistin; as well as its preservation in microbial populations of K. pneumoniae even in the case of limiting the use of this antibiotic.

Journal of microbiology, epidemiology and immunobiology. 2021;98(4):426-433
pages 426-433 views

Evaluation of the ability of cholera vibrios to form a biofilm on the surface of the chitinous shell of a crayfish by real-time PCR

Menshikova E.A., Kurbatova E.M., Vodopyanov S.O., Pisanov R.V., Titova S.V.


Introduction. Most of the bacteria exist in natural ecosystems not in the form of free floating cells; but in the form of biofilms attached to the substrate. One of the most ecologically important substrates is chitin. Vibrio cholerae; like most members of the Vibrionaceae family; has a chitinolytic complex and can degrade chitin. The ability of V. cholerae to form a biofilm on chitinous substrates can explain the mechanism of the formation of an ecological niche for the preservation and transfer of the pathogen to new regions with the likelihood of the formation of new foci of cholera.

Aim — to determine the ability of V. cholerae to form a biofilm on the chitinous shell of crayfish (Astacus astacus) by means of real-time PCR.

Materials and methods. A comparative analysis of the timing of biofilm formation by V. cholerae of different serogroups and toxigenicity was carried out.

Results. In the course of the study; it was found that cholera vibrios were shown to be capable of forming a biofilm regardless the serogroup and toxigenicity. However; toxigenic tcpA+ strains have a higher intensity of biofilm formation than nontoxigenic ones; in which the tcpA gene is absent.

Journal of microbiology, epidemiology and immunobiology. 2021;98(4):434-439
pages 434-439 views

Significance of parenteral viral hepatitis laboratory diagnostics in the Republic of Guinea

Boumbaly S., Serikova E.N., Semenov A.V., Ostankova Y.V., Valutite D.E., Schemelev A.N., Zueva E.B., Balde T.A., Baimova R.R., Totolian A.A.


Rationale. Countries of Africa, especially countries in sub-Saharan Africa, represent a region characterized by high incidence of chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infections. Methods for detection of HBV and HCV in low and middle-income countries differ from those that are used in countries having access to high-cost technologies. The Republic of Guinea is a region with high prevalence of hepatotropic viruses, however, the information on HBV and HCV prevalence in the area is extremely limited, thus emphasizing the significance of this study.

The purpose of the study is to evaluate the need for improving laboratory diagnostics of parenteral HBV and HCV infections in the Republic of Guinea.

Materials and methods. A total of 2,616 samples of blood serum were tested, the samples were collected from apparently healthy residents of the Republic of Guinea during the routine medical checkup. The testing included qualitative detection of HBsAg, anti-HBs IgG, anti-HBcore IgG, anti-HCV IgG antibodies as well as HBV DNA and HCV RNA.

Results. The detection frequency of serological markers of HBV and HCV infections was 80.77% and 18%, respectively. However, HBsAg was detected only in 16.01% of individuals. Tests for detection of HBV DNA were performed among seropositive patients and patients seronegative by other HBV markers, HBV DNA was detected in 22.36% of cases, including 6.07% of HBsAg-negative cases. HCV RNA was detected in 2.2% of cases. Both HCV RNA and HBV DNA were detected in 27 people, including 19 HBsAg-negative cases, thus accounting for 1.03% of the examined group.

Conclusions. The markers that are currently used for laboratory detection of HBV and HCV in the Republic of Guinea are not efficient enough to diagnose reliably all cases. Undoubtedly, there is an urgent need to improve laboratory diagnostics for timely detection of parenteral viral hepatitis. Routine laboratory operations need assays for additional serological and molecular markers of HCV and HBV infections.

Journal of microbiology, epidemiology and immunobiology. 2021;98(4):440-449
pages 440-449 views


Cell and molecular level of strategy of COVID-19 to induce immunodeficiency. Possible therapeutic solutions

Bavykin A.S.


The review considers the nature of clinical and pathological disorders caused by highly pathogenic coronaviruses in the human body, analyzes the causes of systemic damage to various organs and tissues, the strategy of virus reproduction and the associated syndrome of cytokine reactivity with the development of specific immunodeficiency at the molecular level. The most developed approaches to the targeted therapy of cytokine reactivity syndrome and SARS including elements of theranostics — monitoring of molecular targets for targeted therapy — are described. An example of an innovative bioengineering technology associated with the reprogramming of cells of the primary "echelon of defense" with the ability to endow them with highly specific skills of directed destruction of cells infected with a virus is given.

Journal of microbiology, epidemiology and immunobiology. 2021;98(4):450-467
pages 450-467 views


Development of software tools based on multi-agent modeling and implemented in the new generation geographic information system for solving epidemiological problems

Asatryan M.N., Gerasimuk E.R., Strukov D.R., Shmyr I.S., Vekhov A.O., Ershov I.F., Labodin A.V., Nozdracheva A.V., Semenenko T.A., Naroditsky B.S., Pronin A.V.


The aim of the study — demonstration of the capabilities of new generation geographic information system software and agent-based modeling for solving epidemiological problems (on the example of the spread of measles in a metropolis).

Materials and methods. Examples of the use of thematic layers and the functionality of the geoinformation platform, as well as the developed multi-agent model of measles spread in the megalopolis, are given. The measles spread model is presented as following three independent sub-models or nested models: behavior model, infection model, infectious process model. The modularity and independence of the sub-models allow the use

of the necessary statistical and clinical data, both directly related to the studied disease and demographic indicators, which are analyzed and stored in the thematic layers of the platform.

Results. The developed software tools allow visualizing, analyzing and short-term forecasting of the spread of the disease in the study area, with the ability to generate reports, which can be a useful and relevant addition to the daily work of specialists, contribute to the improvement and deepening of practical skills and abilities, in accordance with the types and tasks of professional activities, as well as expand opportunities for assistance in management decision making.

Journal of microbiology, epidemiology and immunobiology. 2021;98(4):468-480
pages 468-480 views


Comparative evaluation of hydrolysates as a basis for the construction of a nutrient medium for the cultivation of Listeria monocytogenes

Khaptanova N.M., Ostyak А.S., Lukyanova S.V., Kuznetsov V.I., Аndreevskaya N.M., Adamovich S.N., Ushakov I.A., Yudenich S.V., Balakhonov S.V.


The objective is to perform a comparative evaluation of the pancreatic hydrolysates prepared from fish and squid to determine the optimal culture medium for Listeria monocytogenes.

Materials and methods. The following raw materials were used in the study: Pacific Herring (Clupea pallasii), Alaska Pollock (Gadus chalcogrammus), Common Roach (Rutilus rutilus lacustris), European Squid (Loligo vulgaris). The raw materials were subjected to enzymatic hydrolysis using the pancreas (according to Hottinger). A study of the physicochemical properties of pancreatic hydrolysates (content of free amino nitrogen (FAN), acidity of fish hydrolysates, the amino acid composition) was carried out.. The specific activity of nutrient media during the cultivation of the test strain L. monocytogenes 766 was assessed by a complex of microbiological methods.

Results and discussion. The highest content of FAN at the end of enzymatic hydrolysis was observed in the pancreatic hydrolysate of the common roach (6%), the acidity of the hydrolysate remained stable from 6th to 13th day of the hydrolysis process (pH 7.2). Pancreatic hydrolysate of the common roach contained a number of amino acids that are most essential for the growth of Listeria. An assessment of the biological properties of nutrient media prepared on the basis of the obtained hydrolysates demonstrated that the best results in terms of sensitivity and germination of L. monocytogenes 766 showed a nutrient medium based on the pancreatic hydrolysate of the common roach. During the cultivation of L. monocytogenes 766 the test strain retained its morphological and cultural properties and did not show signs of dissociation.

Conclusion. The research results have shown that the pancreatic hydrolysate of the common roach is a promising protein basis for the construction of an experimental environment for listeria.

Journal of microbiology, epidemiology and immunobiology. 2021;98(4):481-485
pages 481-485 views


Zinaida Vissarionovna Ermolyeva — the great Soviet scientist-microbiologist and epidemiologist

Tverdokhlebova T.I., Agafonova V.V.



Journal of microbiology, epidemiology and immunobiology. 2021;98(4):486-489
pages 486-489 views

This website uses cookies

You consent to our cookies if you continue to use our website.

About Cookies