Purpose: to identify the features of COVID-19 infection in children at different periods of the epidemiological rise in the incidence in the city of Moscow.

Results. The article presents the observation of 1561 children hospitalized in the State Medical Institution «Children's City Clinical Hospital named after Z. A. Bash-lyaeva DZM» with a diagnosis of a new coronavirus infection COVID-19 during the periods of epidemiological rises in morbidity («2nd and 3rd waves of COVID-19»). An increase in the number of hospitalized children during the «3rd wave of COVID-19», early admission dates from the onset of the disease, due to the lack of treatment effect in outpatient settings, the predominance of school-age children and adolescents, the predominant course of infection with the development of viral pneumonia CT2-3, less often CT3-4, a 10-fold reduction in the number of children with MIS-syndrome, an elongation of the period of viral release in patients.

Urinary tract infections are the second most common infections in children with spreading of antimicrobial resistance among uropathogens currently poses a high epidemiological threat.

Purpose. Analysis of species prevalence and the presence of genetic determinants of antibiotic resistance.

Materials and methods. In the study 215 midstream urine samples were retrospectively analyzed. Samples were obtained during 2017 and 2019 from patients aged 4 weeks to 17 years at the National Medical Research Center for Children's Health Federal State Autonomous Institution of the Ministry of Health of the Russian Federation.

Results. Species of pathogen were identified in 93 samples, while the bacterial composition of other samples was classified as «intestinal flora» (n = 17), «coccus flora» (n = 16) or «mixed flora» (n = 89). The most common types of uropathogens in monopathogenic infections in 2017 and 2019 were Escherichia coli (37.5% and 29.2%, respectively). Among infections caused by multiple pathogens, the most common etiological agents were Pseudomonas aeruginosa and Staphylococcus spp. Among all studied samples, 31.9% contained CTX-M-like genes, 5% VIM genes, 1.8% NDM genes, and 3.0% — OXA-48-like genes, and 5.6% of samples contained two and more genetic determinants associated with resistance, with the most prevalent gene combination being the combination of CTX-M- and OXA-48-like genes. In 69 samples with identified species of uropathogens, resistance profile to antimicrobial, determined by microbiological methods, correlated with detected resistance genetic determinants.

Conclusion. Authors suggest that introduction of testing for the presence of genes associated with antibacterial resistance to general clinical practice would not only provide an opportunity to conduct epidemiological monitoring of the genetic determinants of antibiotic resistance, but also provide an opportunity to select the correct timely treatment of childhood bacteriuria caused by antibiotic-resistant infectious agents.

The purpose is to characterize the clinical picture, immune status and the natural history of HIV infection in the stage of secondary diseases in vertical and parenteral infected children.

Materials and methods. A clinical, laboratory, instrumental, immunological examination of 132 children in the stage of secondary diseases infected with HIV in a vertical way (90; I group) and parenteral way in infancy (42; II group) was carried. Results. The clinical picture of HIV infection in the stage of secondary diseases included various combinations of HIV-associated symptoms, opportunistic infections, tumors, which determines the symptomatology of a particular stage. The use of the Cox regression mathematical model of proportional intensities demonstrated a reduction in the duration of stage 4A (RR 5.8; 95% CI 1.4—10.5; P < 0.001), 4B (RR 3.4; 95% CI 1.8—4.3; P < 0.001) and 4V (RR 4.8; 95% CI 1.2—8.9; P < 0.001) in children of group I. Using the method of multiplying Kaplan-Meier estimates, the significant differences between the time curves from the beginning of the 4A stage (Р = 0.044), 4B (P < 0.001) and 4V (Р = 0.029) before the transition to the subsequent stage in children of groups I and II were established. The content of CD4 lymphocytes in the blood in patients of group I was higher as compared with group II at the time of debut of stages 4A (Me 37.5%, IQI 33—40% and Me 22%, IQI 18—24%; Р < 0.001), 4B (Me 25%, IQI 22—28% and Me 20%, IQI 18—22%; Р < 0.001) and 4V (Me 14%, IQI 12—18% and Me 11%, IQI 10—14%; Р = 0.047).

Conclusion. HIV infection in the stage of secondary diseases in children infected with the vertical way is characterized by more rapid progression compared with parenteral infected in infancy patients, which is associated with the immaturity of the immune system.

The study of a new coronavirus infection (COVID-19) in children is relevant and of interest for practical health care.

Purpose: to identify the clinical and laboratory features of COVID-19 in the context of the six-month dynamics of the pandemic in children of the Orenburg region and to formulate recommendations for optimizing the diagnosis of this disease.

Materials and methods. A retrospective analysis of 2661 results of detecting SARS-CoV-2 RNA (including 170 children) was carried out on the basis of the microbiological laboratory of the Orenburg State Medical University. Age and sex, structure of preliminary diagnoses, main clinical manifestations, frequency of testing and dynamics of the PCR threshold cycle in September 2020 and January 2021 were assessed.

Results. The proportion of children examined in the Orenburg region from September 2020 to January 2021 increased from 4.6 ± 0.6% to 8.1 ± 0.7%. At the same time, the number of PCR + results also significantly increased from 5.0 ± 2.8% to 8.2 ± 2.6% (χ² = 54.81; p = 0). The average age of children was 9—10 years old. The main reason for referral was pre-hospitalization screening not related to COVID-19. The proportion of PCR + results in this cohort was significantly lower in children than in adults. Among the clinically manifested forms in adults, the leading diagnosis was «pneumonia», and in children «ARVI». In childhood, a predominantly asymptomatic course of the disease was recorded. In children, unlike adults, PCR Ct values did not correlate with the severity and duration of the clinical manifestations of COVID-19.

Conclusion. Due to the low diagnostic value of symptoms in children, it is more expedient to focus on epidemiological data and data from the results of laboratory examination methods. When interpreting the results of PCR diagnostics of COVID-19 for prognostic purposes, it is important to take into account the patient's age.

Most researchers agree that the level of protective anti-HBs decreases with age after 3-fold immunization in the first year of life, which requires the introduction of a booster dose at least 5—7 years after the completed vaccination. It is necessary to continue monitoring those vaccinated against hepatitis B in the first year of life, including those from occupational risk groups.

Objective: to assess the frequency and level of anti-HBs 18 or more years after the completed course of vaccination against hepatitis B according to the standard scheme in the first year of life and to identify risk groups that need revaccination.

Of 116 donor students in Moscow, 18—22 years after the completed course of vaccination against hepatitis B according to the standard scheme carried out in the first year of life, in 42.3% of cases, the titer of specific antibodies was determined below the protective level (< 10 mME/ml). At the same time, the share of seronegative individuals among medical students was higher (52.8%). Of 116 donor students, in 38.8% of cases, the titer of protective antibodies was determined in low (10—100 mME/ml) and only in 13.8% — in high (100—1000 mME/ml) and in 5.2% — very high (> 1000 mME/ml) values. Markers of DNA HBV, HBsAg, and anti-HBcor were not detected in any cases. Medical students primarily need a revaccination against hepatitis B without a preliminary study of the initial titers of specific antibodies.

In infectious pathology in infants, staphylococcal infection occupies a leading place, is characterized by the rapid development of intoxication, a purulent-destructive process with the possibility of generalization of infection, affecting the course and outcome of the disease.

The aim of the study was to study the results of treatment of primary staphylococcal enterocolitis, in infants, with the use of antibacterial drugs and their combination with bacteriophages.

Research methods. The frequency of elimination of staphylococcus, the duration of the main symptoms (fever, diarrhea, toxicosis with exicosis) as a result of treatment of primary staphylococcal enterocolitis (confirmed by laboratory) were analyzed in children aged from 1 to 12 months who received inpatient antibacterial drugs (nifuroxazide, azithromycin) or their combination with bacteriophages (staphylococcal, pyobacteriophage). The data accounting period is from January 2017 to December 2020.

The results of the study. The results of treatment of staphylococcal enterocolitis were studied in 4 groups: monotherapy with nifuroxazide (n = 39) or azithromycin (n = 40), a combination of nifroxazide+staphylococcal bacteriophage (n = 41) or azithromycin + piobacteriphage (n = 38). The groups were comparable by gender, age, and clinical manifestations of the disease. Elimination of staphylococcus on the 10th—12th day. treatment with monotherapy with antibacterial drugs was achieved in 31—35%, with their combination with bacteriophages — in 51—64% of patients in each combination (df = 3, p < 0.05). Against the background of combined therapy, the symptoms of the disease (diarrhea, vomiting) were stopped 1.2 times faster; the number of patients with lactase deficiency and intestinal dysbiosis decreased by 1.7—2 times, with monotherapy with antibacterial drugs-by 1.3—1.4 times (df = 3, p < 0.05).

Conclusion. Treatment of primary staphylococcal enterocolitis in children, including antibacterial drugs and bacteriophages, is more effective than monotherapy with antibacterial drugs.

The article presents an analytical review of the works of domestic and foreign authors on the problem of studying the peculiarities of the formation of the intestinal microbiota and risk factors for the development of microdysbiosis in newborns with the activation of opportunistic bacteria, including C. difficile. Special attention is paid to the effect of antibiotics on the state of the intestinal microbiota and the activation of toxigenic strains of C. difficile. Divergent views on the role of toxigenic strains of C. difficile in the development of infectious pathology of newborns are presented.

The paper summarizes the information currently available in the literature on the etiology, life cycle, epidemiology, pathogenesis, pathomorphology, clinical manifestations, diagnosis, etiotropic therapy and prevention of paragonimiasis.

Diagnosis of pneumonia in children is still a debatable issue. Recently, the increase in overdiagnosis has been of pneumonia and, as a result, frequent and unjustified prescription of antibacterial therapy, forming antibiotic resistance in the future. The article analyzes the issues of verification of pneumonia, and also provides data of our own observation about the overdiagnosis of this disease.

Relevance: Infectious diseases are one of the most pressing problems in pediatrics, in particular the COVID-19 pandemic has had a huge impact on society and health.

Purpose of the work: to analyze the frequency of infectious diseases in children of the Udmurt Republic during a pandemic of a new coronavirus infection using the example of rural and urban areas.

Materials and methods: a statistical analysis of the official medical documentation (form No. 12) of the Udmurt Republic «Mozhginskaya regional hospital of the Ministry of Health of the Udmurt Republic» and the Budgetary Establishment of Health of the Udmurt Republic Alnash District Hospital of the Ministry of Health of the Udmurt Republic for 2019—2020 for children with infectious diseases up to 14 years old inclusive was carried out.

Result: the incidence of infectious diseases decreased: in Mozhga it decreased by one third (33%) compared to the previous year (13889 and 9318 cases); in Al-nash experienced a more significant reduction in 2 times (3618 and 1513 cases, respectively). The rate of decline in Mozhga was 33%. The maximum values are traced among the following nosologies: influenza, viral hepatitis, meningococcal infections (the rate of decline was 100%). In Alnash, the rate of decline was 58%, the highest rates were in laryngitis and tracheitis (the rate of decline was 73%). The downward trend in infectious pathology during a pandemic is similar in urban and rural areas.

Conclusion: restrictive measures against COVID-19 contributed to a decrease in the incidence of infectious pathology, which is more transmitted by airborne droplets, but also spread by fecal-oral and contact-household routes. Studying the characteristics of the incidence of infectious diseases during the period of self-isolation can help doctors control the level of morbidity in the future.

In 2014, obligatory medical check-ups of the child population were legislatively introduced in Azerbaijan. At the same time, for the early detection of diseases and various pathological conditions, health services of the country paid special attention to precisely preventive measures which will predetermine both the state of child health, as well as the quality of their life in the future.

In order to increase the efficiency of obligatory medical check-ups, the morbidity rates of the child population of Azerbaijan were analyzed based on the results of preventive medical examinations for the period 2014—2019.

Objective: The article describes a clinical case of severe Epstein-Barr viral hepatitis in a child aged 1.

Materials and methods. The diagnosis of Epstein-Barr mononucleosis was confirmed by repeated isolation of Epstein-Barr virus DNA from the blood by PCR, and IgM to the capsid antigen detection in the blood. Atypical mononuclear cells in blood tests were not detected throughout the disease course.

Results. The main clinical symptoms in the first 2 weeks of the disease included a fever, severe lymphoproliferative syndrome, persistent purulent tonsillitis, and maculopapular rash. Severe hepatic damage developed on 20^th day from the onset of the disease. The fact that the disease had an unusually severe course made it necessary to conduct differential diagnosis with lymphoproliferative and hemophagocytic syndromes. The child received the treatment with low-dose interferon agents (interferon α-2b) in suppositories, glucocorticoids (prednisone 3 mg/kg/day), intravenous immunoglobulins, symptomatic therapy. Acyclovir therapy was not administered. The patient made a complete recovery with full normalization of liver function.

The relevance of monitoring the course of coronavirus infection COVID-19 in combination with comorbid pathology is obvious, since this new infection with immunopathological pathogenesis is not fully understood.

The article presents a clinical case of COVID-19 disease in a 14-year-old teenager from the Moscow region, who developed against the background of severe ulcerative ileocolitis of moderate activity. The new coronavirus infection contributed to the recurrence of ulcerative colitis, which required observation and treatment in a hospital setting.

The examination revealed: mild hypochromic posthemorrhagic anemia, signs of hypercoagulation characteristic of the course of ulcerative colitis; excluded: opportunistic infections, pneumonia, acute intestinal infections and intestinal bleeding.

The standard complex therapy of ulcerative colitis without the inclusion of immunosuppressors made it possible to avoid a more severe and complicated course of the new coronavirus infection. COVID-19 in the teenager was mild, antiviral therapy was not used.