Treatment and prevention of foodborne infection caused by shiga-toxin-producing strains of Escherichia coli (STEC) remains one of the outstanding public health problems. Specific bacteriophages can be considered as one of the ways to control STEC infection. The objective of the study was to search for specific lytic bacteriophages active against epidemic heteropathogenic STEC strain of serotype O104:H4 and to study the sanitizing efficacy of phage in in vitro and in vivo experiments. Seven bacteriophages were isolated from the feces of industrial poultry; the properties of one of them, ECD4, were studied in more detail. It was shown that bacteriophage ECD4 forms negative colonies of about 1 mm in diameter on sensitive strains of E. coli and exhibits pronounced lytic activity against heteropathogenic STEC strain O104:H4, E. coli strain O104:H12 and E. coli C600, as well as lyses 6 out of 8 strains of E. coli O157:H7, 11 out of 17 strains of Shigella flexneri and two strains of Shigella sonnei. It was found that after administration of bacteriophage ECD4 intragastrically or with drinking water to healthy mice, phage particles were detected after 24 h in all experimental animals, in some individuals – after 36 h, and after 48 h phage could not be isolated. Bacteriophage ECD4 is able to penetrate from the intestine into the blood, spleen and liver, where it is detected within 1–12 h. In experiments on a mouse model of STEC-infection caused by E. coli O104:H4, it was shown that phage ECD4 has a sanitizing effect, in particular, it causes a decrease in the concentration of the pathogen in the intestine of animals by 10 and more times. Key words: Escherichia coli, bacteriophage, Balb/c mice, phage lytic activity, shiga-toxin

The incidence of human pasteurellosis is low, but severe lung damage or septicaemia with fatal outcome is possible in the presence of immune deficiency. Information on the etiology, epidemiology, clinical course, diagnosis and etiotropic therapy of the disease caused by Pasteurella multocida is presented. In addition, the article presents a clinical case of primary-septic form of pasteurellosis with lethal outcome, developed in an elderly patient without primary focus and concomitant immunodeficiency. Data on pathological and anatomical changes in severe course of pasteurellosis are presented separately. Key words: lethal outcome, treatment, pasteurellosis, pathomorphology of sepsis, septicaemia, septic shock

There is evidence of the role of microorganisms in endothelial damage and, as a consequence of activation of blood coagulation pathways, thrombosis, which in turn is one of the risk factors for the development of acute cerebrovascular accidents (ACVA). Objective. To analyze the microbiological profile of DNA isolated from thrombus of patients with ACVA. Materials and methods. Fifty-seven thrombus samples obtained lifetime from the vessels of patients with ischemic-type ACVA during thrombectomy and thrombaspiration were selected for the study. All patients with ACVA were in the period of coronavirus infection reconvalescence. Twelve blood samples from patients without infectious diseases were used for comparison. Amplification of DNA isolated from biological material was performed using primers specific to the 16S rRNA gene fragment. The obtained PCR products were sequenced by Sanger sequencing method, with subsequent processing of chromatograms in the BCV package. RDP Classifier was used to determine the taxonomic affiliation of DNA sequences. Statistical analysis was performed in the R environment using Pearson's and Fisher's χ2 criteria. Test results were considered significant at p < 0.05. Results. Using the RDP Classifier, the taxonomic affiliation of 16S rRNA gene fragment amplification products were determined for 43 blood and clot samples. DNA of Actinobacteria and Firmicutes taxa were most represented in the clot samples of patients with ACVA. Of the Firmicutes and Proteobacteria taxa, Firmicutes predominated in thrombi, whereas Proteobacteria predominated in blood. The obtained data are consistent with the data on the key role of systemic intestinal inflammation in the pathogenesis of ACVA. Conclusion. DNA fragments of Actinomycetales, Bacillales, and Clostridiales bacteria found in thrombi of patients with ACVA indicate that they can penetrate the damaged epithelial barrier and promote platelet aggregation and thrombus formation, increasing the risk of ischemic stroke. Key words: ischemic stroke, acute cerebral circulatory disorders, bacterial infection, RDP Classifier

The mucous membranes and skin bordering the environment possess the body's defense system against infectious agents, which has been named “mucosa-associated lymphoid tissue” and includes, among others, the upper respiratory tract, the mouth and the gastrointestinal tract Important components of the defense system are secretory immunoglobulins and the microbiota Decreased levels of secretory immunoglobulins and disruption of the microbiome due to massive pathogen intervention causes weakening of defense mechanisms Various agents are used to stimulate barrier functions The COVID-19 pandemic stimulated the development of topical agents to create passive immunity directly on mucous membranes Numerous variants of monoclonal antibodies, antibodies from eggs and colostrum have been proposed Similar approaches have been used for the therapy of diseases of the oral cavity and gastrointestinal tract. At the same time, the understanding of the importance of using polyclonal homologous antibodies, which are directed to a wide range of pathogens and due to passive transfer of antibodies can provide immediate protection against certain infections, has returned. Human immunoglobulin complexes of three classes – IgG, IgA and IgM – for intranasal administration in the form of drops or sprays, which can be used in immunocompromised, frequently ill and those with contraindications to vaccination, may be a promising tool. Key words: antibodies, human immunoglobulin, infections, passive immunity, antibody preparations, mucous membranes

Objective. The primary objective of this study was to evaluate the efficacy of amcafovir (6HP) in combination with standard ART in previously untreated HIV-infected patients compared to a combination containing tenofovir (TDF) and standard ART. Patients and methods. The study included 221 patients randomized in a 1:1 ratio into the group receiving 6НР (with a dose of 600 mg – 3 capsules of 200 mg once daily – 112 patients) or into the comparison group receiving TDF (300 mg – 1 tablet once daily – 109 patients). In addition to the comparison drugs, all patients received NRTI (3ТС) and Dolutegravir, DTG at standard daily doses. Results. After 24 and 48 weeks of therapy, both regimens showed high virologic efficacy: the proportion of patients with HIV RNA levels <50 copies/mL was 96.97% and 97.98% in the 6НР group and 100% and 96.97% in the TDF group, respectively. The immunologic efficacy of both ART regimens was evidenced by an increase in the median CD4+ lymphocyte count by 210 (6HP) and 191 (TDF) cells/μL after 48 weeks of therapy. Tolerability of both ART regimens was good: only 5 moderate AEs (1 treatment-related AE) were registered. Only 2 patients dropped out of the study due to AEs (grade 2 anemia and mild myalgia) probably/probably related to the study drug. Conclusion. ART regimen including 6HP (amcafovir) + 3TC + DTG is no less effective and safe than TDF + 3TC + DTG and can be recommended as a starting regimen for previously untreated HIV-infected patients. Key words: HIV infection, Antiretroviral therapy, amcafovir (6HP), tenofovir, dolutegravir

The olfactory dysfunction is one of the clinical manifestations of coronavirus infection. Unlike a decrease in the sense of smell, which can be observed with mucosal edema in influenza and other acute respiratory infections, with coronavirus infection, there is often a complete shutdown of the sense of smell – anosmia. This condition can be observed in patients not only in the acute period of infection, but also persist for a long time during the period of convalescence, which significantly reduces the quality of life of such patients. The presented clinical analysis shows, using examples from clinical practice, various variants of the influence of olfactory dysfunction disorders on the quality of life of patients and emphasizes the importance of the problem for the healthcare provider. Key words: coronavirus infection, anosmia, parosmia

One of the main biological characteristics of SARS-CoV-2 is its remarkable ability to adapt to new environmental conditions. Accelerated evolution of the COVID-19 pathogen complicates anti-epidemic measures, including the need to update the antigenic composition of vaccines and maintain current vaccination measures, complicates the prognosis of the infection course, and reduces the efficacy of drugs based on monoclonal antibodies and specific antiviral inhibitors. Under these conditions, the search for new approaches to monitoring clinically and epidemiologically significant variants of the virus that escape the factors of humoral immunity, as well as to the accelerated development of relevant immunobiological preparations, becomes important. This in turn requires the use of approaches to assess the serological properties of new variants, such as neutralization reactions using live infectious virus or immunochemical methods with limited antigen detection. Immuno-PCR (iPCR) is a method which is lacked majority of virus neutralization reaction and immunochemical methods (ELISA and LFT) disadvantages. The iPCR method has many modifications aimed at increasing specificity while reducing background amplification, simplifying staging, and multiplexing. Taking into account the high sensitivity of iPCR, it is possible not only to measure the exact amount of antigen, but also to use the diagnostics in the minimum quantities available, for example, in clinical samples. This fact makes iPCR method high-promising in personalized medicine field. Key words: SARS-CoV-2, coronavirus evolution, immuno-PCR, humoral immunity

Adenoid hypertrophy is a serious medical and social problem due to the high prevalence of this pathology in the paediatric population and a wide range of diseases induced by hypertrophy and chronic inflammation of adenoid vegetations. The causes of its development are numerous, but herpesvirus infections play a leading role as a cause of lymphoid tissue enlargement, which should be taken into account in the tactics of conservative therapy, as well as at the stage of surgical treatment, in order to prevent recurrence. Clinical case description. The patient is 5 years old. Within a year after infectious mononucleosis, she still complains of persistent nasal breathing difficulties, snoring with breathing stops during sleep, frequent respiratory diseases (4–5 times in the previous 6 months), recurrent exudative otitis media. Conservative therapy (glucocorticosteroid (mometasone) endonasally, two 30-day courses) without significant effect. According to the results of examination the following diagnosis was made: Chronic adenotonsillitis. Hypertrophy of the pharyngeal tonsils of the 3rd degree. Hypertrophy of the palatine tonsils of the 3rd degree. Scheduled adenotonsillotomy was recommended. Additional examination revealed Epstein-Barr virus DNA in an oropharyngeal swab and IgG to EBV nuclear antigen in serum. IgM to CMV and HHF-6 in serum and CMV and HHF-6 DNA in an oropharyngeal swab were negative. Endoscopic shaver adenotomy and radio wave tonsillotomy were performed. Combined antiviral and immunomodulatory therapy with the drug inosin pronabex (2 courses of 8 days with 8-day interval at a dose of 50 mg/kg/day in 3 doses) was prescribed. During the following year after the therapy with groprinosin the child had a single acute respiratory infection, no complaints. Endoscopically the nasopharynx is free, at pharyngoscopy hypertrophy of the palatine tonsils of 1 degree is determined. The results of molecular genetic study of swabs from the oropharynx for the presence of EBV DNA were negative. Conclusion. The presented clinical example demonstrates the necessity to take into account the possibility of persistence of herpesvirus pathogens when determining the tactics of management of children with pharyngeal tonsil hypertrophy. Key words: adenoiditis, adenoid hypertrophy, children, inosine pronabex

Pertussis remains an urgent problem of infectious pathology. Every year there is an increase in the incidence of pertussis worldwide, which can be explained by weakening of postvaccinal immunity in older children and adults. In recent years, clinical and laboratory hypodiagnosis of pertussis has been observed, which may be due to low vigilance and ignorance of physicians, dissociation and lack of continuity between pediatricians and therapists, incorrect diagnosis, late referral of patients to a doctor and the development of atypical forms of the disease. Vaccine prophylaxis is currently the main measure to control the spread of pertussis. The article presents a clinical observation of pertussis course in an adult patient, the path of diagnostic search and tactics of management of such a patient. Key words: pertussis, adults, Вordetella pertussis

Objective. To analyze the features of whooping cough in patients under 1 year of age and the state of transplacental protection in children under 1 month of age in modern conditions. Patients and methods. The clinical analysis of whooping cough features in children under 1 year of age is based on observations of 424 patients hospitalized in the Clinical Hospital of Infectious Diseases No 1 in the period of 2017–2019. To verify whooping cough, PCR and ELISA methods were used with the Ridascreen/Bordetella pertussis test system (R-biofarm AMG, Germany), which allows detecting antibodies of various classes (IgM, IgG, IgA). Serological screening to detect antibodies to pertussis antigens was carried out in 52 children under the age of 1 month, hospitalized in various hospitals for newborns in Moscow. Results. Analysis of clinical forms showed that among hospitalized patients, severe forms were observed much more often among children aged 1–3 months, accounting for 38.0 ± 3.8% (63 children) versus 7.0 ± 2.4% (8 children) aged 4–6 months (p < 0.001) and 5.6 ± 1.9% (8 children) aged 7–12 months (p < 0.001). In all age groups, moderate severity of the disease prevailed, occurring in 59.6 ± 3.8%, 86.8 ± 3.2%, and 90.3 ± 2.5% of children, respectively. Analysis of antibodies transplacental transfer in newborns showed that IgG antibodies were detected below the threshold level in 37 (71.1 ± 6.3%) blood serum samples, 3 (5.8 ± 3.2%) corresponded to the threshold values, and 12 (23.3 ± 5.8%) were above the threshold. The predominance of seronegative children proportion suggests a possible high risk of the disease in children of this age with severe forms of whooping cough. Conclusion. Given the severe course and the presence of fatal outcomes in children of the first months of life, it is advisable to vaccinate pregnant women to create passive immunity in newborns. Key words: whooping cough, clinical forms, antibodies, newborns, passive immunity