Vol 11, No 2 (2021)

The activating research interest in the problem of tuberculosis development is due to the increase in cases of drug resistance, coinfection with HIV and hepatitis, and the lack of an effective vaccine. However, the pathogenesis of tuberculosis remains insufficiently studied at present. A significant role is assigned to hereditary factors, as the majority of those infected with Mycobacterium tuberculosis remain resistant to tuberculosis, and only in 5—15% of cases does infection lead to the development of the disease. Despite a long history of research of genetic factors of susceptibility to tuberculosis infection — from the search for monogenic forms of immune dysfunction, associations of individual tuberculosis susceptibility genes, to the analysis of genome-wide associative studies and the assessment of the characteristics of the transcriptional profiles of patients, — the problem of obtaining clinically significant results for the identification and monitoring of risk groups remains particularly acute. The search of differentially expressed genes in groups with different status of the disease (non-infected, latent tuberculosis infection, presymptomatic state, active tuberculosis, recovery from tuberculosis, non-tuberculosis infection) led to identification of a large number of data which is not overlapped in different compared groups, different ethnic groups, in the studies of the whole blood and cellular models. Merging this wealth of data followed by its reanalysis helps to verify and update results. However, there still is a large number of questions concerning our understanding of the functioning of the human organism under the influence of M. tuberculosis. In recent years, new approaches have been used to develop test systems for the diagnosis of various forms of the disease. The review considers up to date results of expression studies of susceptibility to tuberculosis, namely, objects and approaches of research changing over time, forms of the host response to the mycobacteria infection studied, the influence of different factors on the results.

Psoriasis is a multifactorial systemic immune-associated disease. It is assumed that colonic dysbiosis may contribute to its development. In this review we provide the data on colonic dysbiosis in induction and progression of psoriatic inflammation assessing a role for bacterial species: Akkermansia muciniphila, Faecalibacterium prausnitzii and Escherichia coli. On one hand, these bacterial species indicate at state of dysbiotic bacterial communities, whereas on the other hand, they are functionally associated with triggering a chain of events inducing impaired intestinal barrier transforming into chronic inflammation in the colonic mucosa and systemic inflammation. Such a scenario leads to the altered systemic reactivity of innate and adaptive immune cells, impaired function of regulatory immune cells resulting in expansion of the autoreactive skin T-cells and induction of psoriatic inflammation due to molecular mimicry between persistent Streptococcus pyogenes and cutaneous antigens. The psoriatic process is envisioned as a comorbidity with inflammatory bowel diseases. Since dysbiotic changes in psoriasis and inflammatory bowel diseases (e.g. Crohn's disease) display similar features, these diseases might potentially proceed via a similar pathogenetic chain resulting from dysbiotic changes in intestinal microbiota towards impaired intestinal barrier, chronic systemic inflammation and altered anti-inflammatory immune arm. Therefore, the data on pathogenetic pathways of the diseases comorbid with psoriasis are able to uncover yet-unknown pathogenetic components for the latter. Psoriasis as a genetically-determined disease is currently believed to be associated with single nucleotide polymorphisms (SNP) in more than four hundred genes. A role for diverse SNPs in candidate genes involved in psoriasis pathogenetic chain in antigen processing and presentation, migration of immune cells, pro-inflammatory cytokine ligation and production is discussed. Crohn's disease is associated with single nucleotide polymorphisms of the genes encoding intestinal barrier proteins potentially underlying its functional deficiency. In connection with comorbidity and similarity between microbiota-associated pathogenetic psoriasis chain and inflammatory bowel diseases, it is possible to assume that such SNPs accounting for genetic defects in the intestinal barrier are manifested as dysbiotic changes in colonic bacterial community and contribute to progression not only of inflammatory bowel diseases, but psoriasis as well.

The causative agent of plague, Yersinia pestis, is a highly virulent bacterial pathogen and a potential bioweapon. Depending on the route of infection, two prevalent forms of the disease — bubonic and pneumonic, are known. The latter is featured by a high fatality rate. Mortality in untreated bubonic plague patients reaches up to 40—60%, whereas untreated pneumonic plague is always lethal. The development of the infectious process in susceptible host is accounted for by a whole set of pathogenicity factors in plague pathogen displaying various functional modalities being expressed depending on stage of infectious process, providing their coordinated expression. Knocking out any of such factors, in turn, may not either affect microbe virulence or lead to its attenuation. A search for new Yersinia pestis pathogenicity factors and subsequent development of highly effective subunit and live attenuated plague vaccines inducing development of pronounced cellular and humoral immune reactions, and/or assessment of their potential use as molecular targets for plague therapy still remain a pressing issue, as both currently licensed plague vaccines do not meet the WHO requirements, whereas strains of plague microbe isolated in Madagascar are resistant to all drugs recommended for plague antibacterial therapy. Here we summarize an impact of described and newly discovered pathogenicity factors into the virulence of Y. pestis strains and their protective anti-plague activity. An effect of loss of genes encoding regulatory proteins as well as mutations in the genes for various transport systems of Y. pestis on attenuation of virulent strains is described as well. Perspectives for introducing characterized antigens into prototype subunit vaccine as well as some other obtained mutants into prototypes of living attenuating vaccines were assessed. The use of antibiotics for plague treatment has been embraced by the World Health Organization Expert Committee on Plague as the “gold standard” treatment. However, concerns regarding development of antibioticresistant Y. pestis strains accounted for further exploring alternatives to plague therapy. Several research groups continue to seek for other alternative approaches, e. g. treatment with inhibitors of pathogenicity factors. Preliminary data attempting to treat plague patients with pathogenicity factor inhibitors are summarized. Antivirulence drugs targeting key microbial factors represent new promising therapeutic options in the fight against antibiotic-resistant bacteria.

Vaccination of the population is one of the most effective countermeasures in responding to the pandemic caused by novel coronavirus infection. Therefore, scientists all over the world have been working to develop effective and safe vaccines. We have developed a synthetic peptide vaccine, EpiVacCorona, against novel SARS-CoV-2 coronavirus, which is a suspension for intramuscular administration containing a composition of chemically synthesized peptide immunogens of the S protein of SARS-CoV-2 coronavirus conjugated to a carrier protein and adsorbed on aluminum hydroxide. Phase I–II clinical trials of the vaccine have started that consist of two stages: Stage 1 is an open study of the safety, reactogenicity, and immunological activity of the vaccine with the involvement of 14 volunteers aged 18–30 years; Stage 2 is a single blind, comparative, randomized placebo-controlled study with the involvement of 86 volunteers. The study involved volunteers aged 18–60 years; the vaccine was injected intramuscularly twice, spaced 21 days apart between injections. All local reactions in response to vaccine administration were mild, such as a short-term pain at the injection site. There were no signs of development of local or systemic adverse reactions. The two-dose vaccination scheme induced the production of antibodies, specific to the antigens that make up the vaccine, in 100% of the volunteers. Seroconversion with a neutralizing antibody titer ≥ 1:20 was reported in 100% of the volunteers 21 days following the second immunization dose. No seroconversion was reported in the groups of volunteers vaccinated with a placebo. The peptide-based EpiVacCorona Vaccine has low reactogenicity and is a safe, immunogenic product. Clinical Trials Identifier: NCT04527575.

The problem of microbial antibiotic resistance and investigation of its underlying mechanisms is of paramount importance for all fields of clinical medicine, including oncology. The aim of the study was to examine the mechanisms of antibiotic resistance for major pathogens causing purulent-inflammatory complications in cancer patients. Materials and methods. In 2012—2015 there was conducted a prospective examination of 184 cancer patients, including 67 patients at the Department of Surgery no. 1 and 117 patients at the Intensive Care Unit of the Krasnoyarsk Regional Clinical Oncology Center named after A.I. Kryzhanovsky. For this, we collected bronchoalveolar lavage fluid, wound discharge and investigated the material by using bacteriological method, as well as MALDI-TOF. Antibiotic sensitivity was studied as follows: disco-diffusion, double disc method, carbapenem inactivation method, staphylococcal sensitivity — by screening method, PCR, E-test method, and serial dilutions in Muller-Hinton broth. Genotyping and antibiotic resistance mechanisms study were performed by using PCR, M-PCR, and sequencing. The WHONET program (WHO) was used, with significance level set at p < 0.05. Results. Microbiological examination of bronchoalveolar lavage fluid and wound discharge samples allowed to uncover prevalent associations of multi-resistant (MDR) and extremely resistant pathogens (XDR). The microflora of the lower respiratory tract and in the wound secretion in cancer patients were found to be dominated by non-fermenting Gram-negative bacteria reaching up to 44.5% and 48%, respectively; as well as order Enterobacteriales found in 24% and 34.9%, respectively; Gram-positive bacteria — 24% and 17.1%, respectively. Imipenem- and/or meropenem-resistant P. aeruginosa and A. baumannii, K. pneumoniae strains, were assessed for MBL production phenotypically, as well as the genes of the most common VIM, IMP types, whereas A. baumannii — for OXA-23, OXA-40, and OXA-58; and K. pneumoniae — for OXA-48. 20 strains and 16 strains of P. aeruginosa and A. baumannii, respectively, were studied by PCR. It was found that A. baumannii strains formed no MBL, but 56.3% of A. baumannii isolates (9 strains) produced OXA-23 and OXA-40 carbapenemases. Among P. aeruginosa strains there were three of them which possessed VIM (15.0%), whereas the remaining strains formed no MBL, but were resistant to carbapenems being associated with other resistance mechanisms, e.g. efflux, decreased permeability of cell wall etc. Among 6 isolates of K. pneumoniae, 1 strain produced OXA-48. In cancer patients, the percentage of methicillin-resistant strains among all members of the genus Staphylococcus was 48.9% (4 strains belonged to MRSA). PVL- MRSA strains belonged to the clones ST239/spa3(t037)/SCCmecIIIA/tst,sek,seq+ (75%) and ST8/ spa1(t008)/SCCmecIVc/sea+ (25%). MRSA ST239 showed multiple antibiotic resistance: to aminoglycosides (aacA-aphD, aadD genes were detected), linkcosamides/macrolides (the ermA gene was detected), fluoroquinolones (mutations in the GyrA gene — Ser84Leu; in GrlA- Ser80Phe), rifampicin (MIC more than 128 gg/ml; mutations in the rpoB gene are His481Asn, Ile527Met), sulfamethoxazole, tetracycline (tetM gene), and chloramphenicol (66.7% of isolates, the cat gene encoding chloramphenicol acetyl transferase was detected); but sensitive to vancomycin (MIC 1.0 gg/ ml), linezolid in 100% of cases. MRSA ST8 are resistant to aminoglycosides (aacA-aphD, aadD genes), lincosamides/macrolides (ermC gene), tetracyclines (tetK gene), chloramphenicol (cat gene); and 100% sensitive to fluoroquinolones, rifampicin (MIC 0.006 gg/ml), sulfamethaxazole, vancomycin (MIC 1.0 gg/ml), daptomycin (MIC 0.094 gg/ml), linezolid (MIC 0.75 gg/ml). Conclusion. Thus, it was found that members of the order Enterobacteriales, A. baumannii, P. aeruginosa and MRSA retain high resistance to a large number of antibacterial drugs of almost all classes. These data should be taken into account while choosing proper antibiotic therapy, as well as controlling spread of nosocomial infections caused by multiresistant microorganisms.

Arginine deiminase is one of three enzymes constituting the arginine deiminase system in bacteria. It was demonstrated that arginine deiminase exerts anti-proliferative effects on some primary and immortalized mouse and human cells. It is assumed that the inhibitory effect of arginine deiminase on cell proliferation might be related to its ability to result in the arginine exhaustion. T-lymphocytes depend on arginine for proliferation, T-cell receptor complex expression, and the differentiation of memory cells. The aim of the current study was to investigate an impact streptococcal arginine deiminase on functions of human peripheral blood lymphocytes. For this, we comparatively analyzed effects of Supernatant of Destroyed Streptococcal Cells (SDSCs) derived from parental strain S. pyogenes M49-16 and its isogenic mutant S. pyogenes M49-16delArcA bearing inactivated arginine deiminase gene (ArcA) on immune cell functions. An impact of supernatants on cell viability was estimated by staining with DAPI dye. Cell proliferation was assessed by MTT-test and flow cytometry by using the method based on intracellular protein staining with vital fluorescent CFSE (carboxyfluorescein succinimidyl ester) dye. In addition, the level of lymphocyte tyrosine phosphatase CD45 expression in various culturing conditions was evaluated. It was demonstrated that S. pyogenes M49-16 SDSCs had no impact on cells viability. Parental strain-derived SDSC exerted virtually no effect on intact cells proliferation, but considerably suppressed ConA-induced cell proliferation. At the same time, mutant strain-derived SDSC significantly stimulated spontaneous cell proliferation, but not that one after mitogen exposure. It was observed that increased proliferation was accompanied by upregulated CD45 expression, although it was not significant in all cases. These data allow to conclude that bacterial arginine deiminase could be one of pathogenicity factors able to limit lymphocyte proliferation and immune response and could be a part of pathogen strategy to suppress immune response in order to improve bacterial growth and dissemination.

Assisted reproductive technologies (ART) are one of the most effective ways in fighting infertility, but their effectiveness is influenced by various factors. Our study focuses on examining importance of risk factors underlying ART failure related to altered microbiome pattern in the female reproductive system. The case-control study was based on conducting a laboratory examination of 129 infertile couples applied to the Department of Assisted Reproductive Technologies due to failure of in vitro fertilization (IVF), whereas control group consisted of females with successful progressive pregnancy after ART. Chlamydia, herpes virus and cytomegalovirus were assessed by using PCR and ELISA, whereas culture method was used to detect Trichomonas vaginalis in vaginal swabs and ejaculate applying Trichomonas Modified CPLM Medium (HiMedia, India) followed by microscopy. In addition, the qualitative and quantitative composition of the vaginal biocenosis was studied with multiplex RT-PCR by using Femoflor-16 kit (DNA-technologies, Russia). Serological tests were based on measuring IgG and IgA antibodies against Chlamydia trachomatis in ELISA (diagnostic kits purchased from Vektor Best, Russia; NovaTec, Germany; ImmunoComb, Israel) as well as antibodies against immediate early HSV-1/2 proteins (BioService, Russia) and immediate early HHV-5 proteins (Vector Best, Russia). C. trachomatis and herpesvirus DNA was measured by using PCR diagnostic kits Amplisens (Interlabservice, Russia). It was found that sexually transmitted infection agents were highly prevalent in infertile couples applying to the hospital for IVF. Significant factors for non-pregnancy were vaginal dysmicrobiocenosis (OR = 7.5 (95% CI 1.04—54.1), p = 0.02) and detected T. vaginalis (OR = 2.6 (95% CI 1.12—6.4), p = 0.01). Dysbiosis of the reproductive system, including those occurring due to trichomonas infection is associated with lowered ART effectiveness. It is evident to timely detect urogenital infections and dysbiosis while preparing infertile couples for IVF cycles.

The streptococcus group consists of multiple species of globular Gram-positive facultative anaerobic bacteria, the classification of which is based on assessing their capacity to erythrocyte hemolysis. The viridans group streptococci produce a green coloration being a part of normal microflora in the oral cavity. However, in case of developing immunodeficiency states, oncology, and neutropenia, this pathogen can cause diseases such as bacteremia, sepsis, endocarditis, as well as pneumonia in some cases. Respiratory diseases commonly require medical assistance in HIV-infected patient cohort. The role of commensal S. viridans in development of bacterial diseases in HIV-infected patients remains poorly examined. A potential association between S. viridans and other bacterial communities, including pathogenic microorganisms is obscure. In addition, it might be worth evaluating sensitivity of S. viridans to antibacterial agents in regions with high HIV infection incidence. The aim of the study was to evaluate sensitivity to antibiotics in sputum viridans group streptococci collected from HIV-infected patients with symptomatic pneumonia. Materials and methods. The data on sputum microbiological study conducted within the 01.01.2012—01.01.2019 interval were collected from all HIV-infected patients with suspected pneumonia (n = 684) and analyzed at the Infectious Clinical Hospital No. 1 named after D.M. Dalmatov, among which S. viridans was detected in 193 patients (28.2%). Bacteriological examination of patient samples was conducted to isolate pure bacterial culture by using standard methods. Next, S. viridans was assessed for sensitivity to antibacterial agents (n = 78) according to the 2018 clinical recommendations. Initially, antibiotic resistance was assessed by disk-diffusion method as a routine approach broadly used in clinical laboratory. After that, the minimal inhibitory concentration was measured by using AutoScan 4 Microscan analyzer (bacteriological semi-automatic analyzer, Beckman Coulter, USA) to identify and determine antibacterial sensitivity. Results. A disk-diffusion method allowed to find in sputum samples streptococci resistant to penicillin in 28.2% cases, ampicillin — in 42.3% and cefazolin — in 43.6%. While assessing the minimal inhibitory concentration for antibacterial agents, similar data were obtained. Good sensitivity was found for cefotaxime, ceftriaxone, cefepime, fluoroquinolones and vancomycin.

Investigating a role for pro- and anti-inflammatory cytokines in immune and inflammatory response represents one of the most pressing topics in current immunology. There have been accumulated a great body of data regarding the cytokine status during inflammatory processes in gastrointestinal tract. However, many issues remain poorly elucidated. Moreover, most of the studies were mainly aimed at examining biopsy material cytokines collected from various parts of the gastrointestinal tract or gastric juice. Here we present the data on investigating the features of cytokine production in patients with allergic rhinitis combined with H. pylori-associated diseases of the upper gastrointestinal tract. A total of 225 patients aged 18 to 40 years (mean age 29.5±6.74 years) were examined, among which 43 patients suffered from allergic rhinitis, 66 patients had inflammatory diseases of the upper gastrointestinal tract (chronic gastritis/gastroduodenitis), and 69 patients — allergic rhinitis with concomitant inflammatory diseases of the upper gastrointestinal tract. Patients were stratified to various study groups depending on diagnosed allergic rhinitis and H. pylori infection. Serum IL-6 and IL-8 level and complete blood cell count were measured. Statistical significance for difference in parameter frequencies between independent groups was assessed by using Fisher's exact test or χ² criteria. It was shown that serum IL-6 level in H. pylori-negative patients was within the reference interval with single spikes, whereas its production was markedly increased in patients with H. pylori infection regardless of allergic pathology. Frequency of subjects with elevated serum IL-8 level was comparable between groups of patients with gastrointestinal diseases, but significantly higher than that one in the control group. An interdependence between serum IL-8 level and white blood cell count was found, which is of interest for predicting development of the inflammatory process. Thus, the serum IL-8 level during the upper gastrointestinal tract inflammatory diseases was increased regardless of verified of H. pylori infection and allergic rhinitis, whereas increased IL-6 serum level was observed solely in H. pylori-positive patients.

22 февраля 2021 года на 73 году после тяжелой болезни ушел жизни один из ведущих сотрудников нашего института — заведующий лабораторией диагностики вирусных инфекций отдела вирусологии ФГБНУ НИИВС им. И.И. Мечникова, доктор медицинских наук, профессор Вячеслав Федорович Лавров.