Vol 10, No 3 (2020)

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Here we provide the assessment of COVID-19 epidemic in Italy, which scale has led to serious challenges both for society and national health care system. Despite timely information regarding the pandemic spread of the novel coronavirus infection, the country’s health care was not prepared to dramatically increased rate of patients with viral pneumonia at the first stage of the epidemic, infection control measures were not fully implemented that also led to spread of infection among health care workers. Socially vulnerable population groups did not seek timely medical care due to the lack of hospital facilities as well as well-trained medical personnel. At the second stage of developing epidemic, were also delayed and executed at varying timepoints in neighbor regions, with sustained insufficient management after implementing them that was reflected as ongoing rise of epidemic curve over long time. Delayed execution of anti-epidemic restrictive measures aimed at fighting against ongoing epidemic resulted in substantially increased morbidity and mortality among vulnerable population groups and retarded rate of decreasing COVID-19 epidemic curve. Analyzing response measures taken in Italy against COVID-19 epidemic should be appreciated by other countries while dealing with the current pandemic and preparing to react to novel biological threats in the future.

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.

The spread of the novel coronavirus infection (COVID-19) makes the search for new approaches to prevent the infection of great importance. As one of the relevant approaches, the vaccination of risk groups with BCG vaccine has recently been suggested. BCG (Mycobacterium bovis, Bacillus Calmette–Guérin) is a live vaccine for tuberculosis, which is used in many countries with a high tuberculosis prevalence and helps preventing childhood tuberculosis, primarily, military disease and tuberculosis meningitis. Whether BCG may be used to increase the protection against COVID-19 is currently a question of debates. The review considers scientific background underlying possible impact of BCG in increased protection against COVID-19. BCG is able of inducing the heterologous and trained immunity, and its capacity to stimulate antiviral immune response has been demonstrated in experimental animals and humans. Our comparison of the dynamics of COVID-19 morbidity and mortality in countries with different BCG vaccination policies has demonstrated a milder course of COVID-19 (i.e., a slower increase in disease cases and mortality) in countries where BCG vaccination is mandatory for all children. However, an association between BCG vaccination and a milder COVID-19 course is not obligatory direct. Other factors that may affect the association, such as the level of virus testing, the rigidity and the speed of quarantine implementation and others are discussed. An important argument against a role of BCG in the protection against COVID-19 is that BCG is given in childhood and may hardly induce long-lasting immunity. Because mandatory BCG vaccination is implemented in countries with high TB burden and because in these countries latent tuberculosis infection is widely spread, we suggest a hypothesis that latent tuberculosis infection may contribute to the maintenance of heterologous/trained antiviral immunity in countries with mandatory BCG vaccination. Four countries have recently initiated clinical trials to investigate whether BCG vaccination can increase the level of protection against COVID-19 in risk groups. The results of these studies, as well as COVID-19 epidemiological modeling will help understanding the impact of BCG in the level of the protection against COVID-19. Performing analogous clinical trials in Russia seems appropriate and scientifically sound.

Rickettsialpox is an urban zoonosis caused by Rickettsia akari. To date R. akari is the only well-characterized mite-borne member of the spotted fever group. It is transmitted by the mouse mite, Liponyssoides sanguineus, commonly found on peridomestic rodents. While the disease was first discovered in New York City in 1946, a few years later a similar outbreak occurred in the Ukraine SSR. Numerous serosurveys and diagnosis of sporadic cases of rickettsialpox suggest its global distribution; however, the actual contemporary geography of rickettsialpox and its incidence are unknown. Rickettsialpox is characterized by the classic clinical triad found in rickettsioses of a black eschar, high fever, and rash but the latter is atypical as it is papulovesicular. Dermatological manifestations and the progression of rickettsialpox may mimic other infectious and noninfectious syndromes, including sexually transmitted diseases. The purpose of this review is to increase awareness of this unique disease through reanalysis of classic and contemporary clinical descriptions of rickettsialpox, evaluation of its worldwide distribution, and updates on the public health importance of the disease as well as the ecology and vector associations of R. akari. Our review data suggests that only limited genetic diversity exists among the available isolates of R. akari associated with previous outbreaks; additional effort is still required to define specific genetic markers permitting direct surveillance, accurate and reliable diagnosis, tracking and studying of the vector and host associations of contemporary isolates. The potential of R. akari to cross into other vector species emphasizes the necessity for detection of outbreaks of the disease in new regions of the world and in novel ecological settings. We describe existing gaps and limitations in our current understanding of the pathogenesis of rickettsialpox, the epidemiology of this disease and the genetic diversity of R. akari. We propose research priorities for what is needed to improve our understanding of this neglected rickettsial disease and its etiologic agent.

Rickettsia akari, an obligately intracellular bacterium, is the causative agent of the cosmopolitan urban disease rickettsialpox. R. akari is an atypical representative of spotted fever group rickettsiae (SFG) as it is associated with rodent mites rather than ticks or fleas; however, only limited information is available about the degree of genetic variability found among isolates of R. akari. We examined 13 isolates of R. akari from humans, rodents and mites in the USA, the former Soviet Union, and the former Yugoslavia made between 1946 and 2003 for diversity in their tandem repeat regions (TR) and intergenic regions (IGR). The 1.23 Mb genome of R. akari strain Hartford CWPP was analyzed using Tandem Repeat Finder software (http://tandem.bu.edu) and 374 different TRs were identified, with size variation from 1 to 483 bp and with TR copy numbers ranging between 21 and 1.9, respectively. No size polymorphisms were detected among the 11 TR regions examined from 5 open reading frames and 6 IGR. Eighteen non-TR IGR’s were amplified and sequenced for the same isolates comprising a total of 5.995 bp (0.49%) of the Hartford CWPP strain chromosome. Three single nucleotide polymorphism (SNP) sites were detected in two IGR’s which permitted separation of the five R. akari isolates from Ukraine SSR from the other eight isolates. In conclusion, this is the first study reporting genetic heterogeneity among R. akari isolates of different geographic origins. Further exploration of this genetic diversity is needed to understand better the geographic distribution of R. akari and the epidemiology of rickettsialpox. The potential of mites as hosts for other rickettsial agents also needs further investigation.

Objective: to examine activity and correlative relations for peripheral blood lymphocyte NAD (P)-dependent dehydrogenases in young children with recurrent respiratory infections with hypertrophy of the pharyngeal tonsils and bronchial obstructive syndrome.  Methods. 89 children, aged 1–3 years, with recurrent respiratory infections were examined, including 35 children with hypertrophy of pharyngeal tonsils (HPT) and 54 children — with bronchial obstructive syndrome (BOS). Control group contained 20 age-matched healthy children. Activity and relations for peripheral blood lymphocyte for NAD(P)-dependent dehydrogenases were assessed by using bioluminescent method proposed by А.А. Savchenko and L.N. Suntsova (1989).  Results. It was found that children with recurrent respiratory infections displayed altered enzyme status in peripheral blood lymphocytes. In particular, activity ribose-5-phosphate- and NAD(P)-dependent metabolic events as well as substrate flux via the tricarboxylic acid cycle were elevated that was paralleled with decreased lactate dehydrogenase anaerobic reaction, thereby implicating a role for malate-aspartate shunt in the energy turnover, substrate efflux from the tricarboxylic acid cycle into amino acid metabolic pathways as well as activity of glutathione reductase. Moreover, features of altered enzymatic profile in peripheral blood lymphocytes were uncovered, which depended on type of complication related to respiratory infection. In addition, children with hypertrophy of pharyngeal tonsils were featured with increased influx of lipid catabolism products into glycolysis, elevated level of malic enzyme activity and decreased pyruvate production. However, children with bronchial obstructive syndrome were found to have decreased glycerol-3-phosphate dehydrogenase activity resulting in lowered shunting activity of slow reactions in Krebs cycle and increased influx of amino acid metabolism intermediates into the tricarboxylic acid cycle. Reshaping of enzymatic profile in peripheral blood lymphocytes depended on type of complications coupled to respiratory infections (ENT-pathology or BOS syndrome). A correlation analysis revealed features of relationship between parameters of NAD(P)-dependent dehydrogenase activity in peripheral blood lymphocytes found in children with hypertrophy of pharyngeal tonsils and bronchial obstructive syndrome marked by quantity, modality and power of correlative links.  Conclusion. Children with the recurrent respiratory infections require metabolic therapy aimed at restoring intracellular pathology-driven metabolic processes in immune cells.

Here, we provide an analysis on 1996–2016 St. Petersburg tick-borne encephalitis (TBE) epidemiological and ecological data. In particular, two main TBE transmission vectors were observed in St. Petersburg: Ixodes persulcatus Ixodes ricinus. TBE tick contamination was 0.61% as shown by ELISA and polymerase chain reaction data. It is found that number of subjects seeking for medical aid due to tick bites rises, whereas TBE incidence declines. In particular, a mean 1996–2002 vs. 2010–2016 tick-bite incidence rate increased from 141.9 up to 288.9, respectively. Despite that the Leningrad region is a major area for TBE spread, however, a risk of exposure to tick bites as well as TBE infection exists even in the city of St. Petersburg. In connection with this, around 1,000 subjects undergo tick bites within the city limits. Moreover, whereas a 1996–2002 mean TBE incidence rate was 1.66, it decreased in 2010–2016 down to 1.17. A peak TBE incidence was documented in St. Petersburg Kurortny, Pushkinsky and Primorsky districts. In addition, males vs. females suffered from TBE at higher frequency in Russian Federation, with its peak incidence rate being reported in children under 14 that differs St. Petersburg from the most of other regions in the Russian Federation. A seasonal distribution of TBE cases in St. Petersburg does not differ from that one for the remainder of Russian regions, which displays a spring-summer seasonality lasting from April to September. Of note, 1996–2016 St. Petersburg TBE mortality was 1.37%. A coverage of TBE vaccinated population tends to rise but still remains at low level (0.25–0.58%). Lack of reported TBE cases in occupationally threatened human cohorts evidences about efficient preventive measures. Detection of TBE virus-specific serum antibodies in 5.0% apparently healthy and unvaccinated residents in St. Petersburg significantly complements the official TBE recording data and provides a more accurate understanding of its actual spread.

Current study performed to estimate the phagocytic activity of blood monocytes of varying phenotypes exposed to MRSA and MSSA strains.  Objects: Blood monocytes were collected from 25 healthy adults (age: 25–45 years). Live suspensions of MRSA/MSSA strains were used at concentration of 106 colony-forming units (CFU)/mL.  Metods. Phagocytic functions were estimated by using fluorescein isothiocyanate (FITC)-labelled MRSA and MSSA strains followed by running flow cytometry on FC 500 series flow cytometer (Beckman Coulter, USA). Whole peripheral blood cells were directly labelled with immunofluorescently tagged monoclonal CD14-PE/CD45-ECD/HLA-DR-PC5/CD16-PC7 antibodies (Beckman Coulter, USA). Respiratory burst intensity was evaluated in monocytes by measuring activity of lucigeninand luminol-dependent spontaneous and induced chemiluminescence. Monocytes were induced by using live suspension of MRSA/MSSA strains at a concentration of 106 CFU/mL. Results and discussion. While studying luminol-dependent monocyte activities after exposure to MRSA vs. MSSA, it was observed a 3.5-fold decreased curve square, whereas lucigenin-dependent chemiluminescence was increased by 6-fold. Compared to MSSA exposure, index of activation (IA) was decreased by 1.1-fold in response to MRSA exposure that was confirmed by lowered release of reactive oxygen species (ROS) from monocytes in response to MRSA exposure. Moreover, IRSS increased by 1.3-fold upon MRSA exposure. Examining monocyte oxygen-independent phagocytosis against MRSA vs. MSSA revealed significantly increased phagocytic number and concomitantly decreased phagocytic index. An evaluation of the activities of various monocyte subsets in response to MRSA vs. MSSA revealed increased phagocytic index by 1.5-fold for CD14^lowCD16⁺ and CD14⁺CD16⁺ monocyte subsets as well as 3-fold for CD14⁺CD16^– monocytes. Counts for all phagocytic subsets were decreased (1.4-, 1.5- and 4-fold for CD14^lowCD16⁺, CD14⁺CD16⁺ and CD14⁺CD16– monocytes, respectively). To summarize, intensity of the respiratory burst was lowered upon MRSA exposure and percentage of monocyte subsets. Overall deficiency of superoxide anion production was observed in response to MRSA. In contrast, oxygen-independent event revealed phenotypic changes in frequency of peripheral blood monocytes upon MRSA exposure. We observed that CD14⁺CD16^– classical monocytes were more rapidly activated. Conclusion. Thus, we concluded that CD14⁺CD16^– monocytes became more rapidly activated but exhibited less effective phagocytosis, whereas CD14⁺CD16⁺ and CD14^lowCD16⁺ monocytes were more slowly activated and demonstrated stronger phagocytic activity.

The use of whole genome sequencing, standard analyze methods and international databases allows to detect international high-risk clones of food-borne pathogens, to assess their evolution and geographical distribution due to international trade of animal food products and farm animals. In Saint-Petersburg, Russian Federation, Salmonella Newport, Salmonella Kentucky and Escherichia coli O26:H11 of well-known international high-risk clones were first identified from patients with diarrhea. Two S. Kentucky strains isolated in 2015 and 2019 were identical to the international clone ST198 widely distributed in European countries: had multidrug resistance, high-level fluoroquinolone resistance (MIC of ciprofloxacin  >  32,0 mg/l) due to three single-nucleotide substitutions in the gyrA (Ser83Phe and Asp87Asn) and parC (Ser80Ile). In 2008, a multidrug resistant S. Newport strain resistant to extended-spectrum cephalosporins due to AmpC-cephalosporinase CMY-2 was isolated, belonging to the international clone of S. Newport MDR-AmpC/CMY-2  which caused sporadic cases and outbreaks in the USA and Europe in the 2000s. The plasmid containing the bla_CMY-2 had a PstI-restriction profile, one of the most prevalent in the international clone. E. coli O26:H11 strains, isolated in Saint-Petersburg,  produced the shiga-like toxin STX1 (stx1a), had additional virulence genes: ehxA (enterohemolysin), katP (catalase peroxidase), espP (serine protease), as well as cba (colicin B), gad (glutamate decarboxylase), cif (type III secreted effector), iss (increased serum survival), belonged to the phylogenetic group B1 and the international high-risk clone  E. coli O26:H11 ST21 widely distributed in Europe and the USA. 25% of the strains had multidrug resistance and produced CTX-M extended spectrum beta-lactamases. In the Russian Federation E. coli O26 is consider as the pathogen of diarrheal diseases and registered as Enteropathogenic E. coli in routine bacteriological laboratories without detecting of H-antigen and shiga-like toxins.

Acute intestinal infections, including intestinal amebiasis, remain a pressing public health problem. Amebiasis still represents an important and partially solved problem to health care. In the Astrakhan region, intestinal amebiasis is being continuously recorded. We analyzed the clinical picture of acute intestinal amebiasis in 150 adult patients dominated by female patients comprising 60.7%, aged 18 to 79 years old, and treated within 2010–2016 at the Regional Infectious Clinical Hospital. All patients were mostly of young and middle age (up to 50 years) — 108 patients. More than 50% of patients were admitted to the hospital within the first three days of the disease. However, in 35 cases (23.3%), late hospitalization was carried out (5 days after the onset). Proper diagnosis was made to 44 patients (29.3%), most commonly diagnosing preliminarily with acute gastroenteritis and acute dysentery. All cases of intestinal amebiasis were confirmed by detecting in the feces of patients with a vegetative form of entamoeba histolytica. The disease was featured with sporadic course, being mostly recorded during the summer-autumn period (78.0%). In 142 patients (94.7%), the moderate severity was observed. Cardiovascular disorders were mainly found in severe amebiasis as well as patients comorbid with cardiovascular diseases. A coprological method was used to confirm the diagnosis. Microscopic examination of feces was carried out immediately after defecation (warm type). A combination therapy was applied to patients with intestinal amebiasis. A great attention was paid to patient nutrition: high-protein sparing diet, grated food. Patients with ulcerative colitis received individualized diet (restricted carbohydrates, exclusion of milk and fiber). Etiotropic therapy was carried out with using 5-nitroimidazole preparations: metronidazole (Trichopol, Flagin, Tiberal), MacGioror, Tinidazole (Phasycin) combined with tetracycline. The treatment included group B vitamin cocktail, methyluracil (suppository), enzymes (creon, mezim, pancreatin), enterosorbents (smecta, polyphepan, enterosgel), antispasmodics (no-spa, drotaverin). Patients were administered with therapeutic microenemas containing furacilin solution, rosehip oil, and sea buckthorn oil. Infusion therapy consisting of polyionic solutions was applied by assessing blood electrolyte level. Fresh frozen plasma and albumin were transfused upon decline of serum protein and albumin level. Packed erythrocytes Erythrocyte mass and hemostatic drugs were injected in case of severe intestinal amebiasis if indicated: dicynone, cryoprecipitate, and calcium preparations. Finally, anemia cases were treated as well. In all cases, the disease outcome was favorable, without any mortality. Complications were noted in the form of intestinal bleeding observed in 6 patients (4.0%), wherein amebiasis proceeded together with ulcerative colitis. Acute intestinal amebiasis is currently featured with typical clinical picture that proceeds with less severe symptoms. Intestinal bleeding was observed in patients with intestinal amoebiasis in combination with ulcerative colitis. Chronization of intestinal amebiasis occurs in single cases (3.9%).

COVID-19 is an acute respiratory infection caused by SARS-CoV-2 coronavirus causing pneumonia, lesions in the cardiovascular system and other organs, high mortality risk, especially in geriatric patients. Due to the great relevance, this study was aimed at describing the case of severe COVID-19 with development of multiple organ failure. Materials and methods. Available accompanying medical documentation (outpatient charts, medical history) was analyzed. Clinical and morphological analysis was carried out by providing description of macro- and micropreparations; histological methods (hematoxylin and eosin staining, Lee reaction) were used. Results. Female patient K.G., 69 years old, was hospitalized to the therapeutic department diagnosed with coronary heart disease. Acute coronary syndrome with ST segment elevation was made on 04/20/2020. A competing diagnosis: severe community-acquired bilateral multi-segmental pneumonia. The patient’s condition was aggravated wile applying therapy followed by biological death occurred. An autopsy revealed bilateral subtotal hemorrhagic pneumonia. Macroscopic lung examination demonstrated “lungs filled with red fluid”. In the brain — perivascular and pericellular edema, hyalinosis, blood stasis and sludge, marked dystrophic and necrotic neuronal changes. Cardiomyocyte fragmentation, areas of perivascular sclerosis with inflammatory infiltrates as well as erythrocytic sludge are found in the heart and blood vessels, respectively. A weak positive reaction according to Lee method was observed. Such clinical and morphological case demonstrates along with lung damage involvement of the heart resulting in acute coronary syndrome (morphologically manifested by ischemic myocardial dystrophy) and the brain. Thus, premorbid background in elderly patients results in developing acute pulmonary heart failure, pulmonary and cerebral edema.

The aim of the study was to carry out clinical and microbiological testing of selective growth medium Acinetobacter phenylalanine agar to isolate and identify bacterial species belonging to the Acinetobacter calcoaceticus — Acinetobacter baumannii complex (ACB complex). For this, 400 samples of clinical material (wound discharge, blood, urine, bronchoalveolar lavage) were examined in 2018 in the Clinical and Bacteriological Laboratory of the Military Medical Academy by using routine assays (seeding on blood agar growth medium, pure culture isolation and identification by using biochemical assays as well as VITEK 2 microbial identification system, bioMerieux) and plating together with growth medium Acinetobacter phenylalanine agar selective to Acinetobacter spp. owing to L-phenylalanine as a sole nitrogen and carbon source additional selected with trimethoprim. ACB complex Acinetobacters were identified 18–24 hours later after incubation at 37°C by emergence of typical colonies on selective medium. Control tests for cytochrome oxidase as well as oxidative/fermentation (OF)-glucose test by using peroxide-hydrogen microvolume method (for 1 h) allowed to rapidly distinguish ACB complex Acinetobacters from other bacteria as well as from Acinetobacter spp. unable to glucose oxidation. Next, species identity for all isolated Acinetobacter strains was established by using matrix-activated laser desorption/ionization with time-of-flight mass spectrometry (MALDI-TOF MS). It was found that by using novel vs. routine assay Acinetobacter spps. were isolated in 26 (18 samples — in monoculture, 8 — in association with Pseudomonas aeruginosa or Klebsiella pneumoniae subsp. pneumoniae with tiny associate colonies) vs. 20 (7 — in monoculture, 13 — in association with Pseudomonas aeruginosa, Klebsiella, Escherichia, Citrobacter, Providencia, Staphylococcus, Enterococcus, C. albicans). Using MALDI-TOF MS method revealed that 25 out of 26 Acinetobacter strains isolated on selective growth medium belonged to the ACB complex (A. baumannii — 23, A. pittii — 2), whereas one strain (A. baylyi) did not belong to ACB complex. Hence, the diagnostic specificity of the Acinetobacter phenylalanine agar synthetic growth medium for isolation and identification of the A. calcoaceticus — A. baumannii complex species comprised 96.2%, with diagnostic sensitivity exceeding that one for routine assay by 25%. Use of selective growth medium accelerates research by allowing to isolate and identify ACB complex Acinetobacter spp. 18–24 h later after plating clinical material. Selectivity of growth medium was potentially stable, as its major trophic selection factor did not depend on acquired bacterial antibiotic resistance, which is also suitable as a synthetic growth medium for standardized studies.