Microflora of sputum and autopsy material of patients with COVID-19.

The rapid spread of a new coronavirus infection in the country actualizes the conduct of bacteriological studies of clinical material obtained from the respiratory tract of patients with COVID-19. During the experiments, 230 sputum samples and 260 autopsy lung samples from patients with COVID-19 were analyzed. 946 high-risk strains were isolated and identified by MALDI-ToF mass spectrometry on a Microflex LT instrument (Bruker®). According to the results of bacteriological cultures of sputum, a predominance of gram-positive ones was revealed, amounting to 50.5% (222 strains) of the total number of isolated pathogens. However, falling into this group is manifested by natural representatives of the microflora of the human mucous membranes from the genera Streptococcus, Rothia and Lactobacillus (109 strains in total), which can be manifested by the detection of improper sputum collection, causing contamination by the substance of intense salivation and nasopharyngeal discharge. In turn, the "classic" gram-positive causative agents of pneumonia were detected much less frequently: S. aureus in 5 cases, S. pneumoniae in 6 patients. The causative agents in the order Enterobacterales are represented by 42 strains, among which the most likely species are K.pneumoniae (27 strains). In the group of non-fermenting gram-negative bacteria, A. baumanii (29 strains) prevailed, and P. aeruginosa was also identified in 2 cases. When analyzing the results of a microbiological study of autopsy material (lungs) of patients with COVID-19, significant differences in the qualitative and quantitative composition of the microflora were revealed, compared with sputum. In the group of gram-positive bacteria, 15 strains of the natural microflora of the mucous membranes were identified, while sensitive species dominated among gram-negative pathogens: K. pneumoniae (102 strains), A. baumanii (75 strains), P. aeruginosa (11 strains). Regular microbiological monitoring is essential for antibiotic therapy and prevention of secondary bacterial infection. In the event of a fatal outcome, the results of microbiological analysis of autopsy material can determine the cause of death of the patient.

[Results of immunoprophylaxis of HIV-infected patients with 13-valent conjugated pneumococcal vaccine].

AIM: To assess changes in the composition of the microflora of the upper respiratory tract and indicators of cellular immunity 1 year after the administration of 13-valent conjugated pneumococcal vaccine (PCV13) in adult HIV-infected patients. MATERIALS AND METHODS: Were recruited 100 participants of both sexes (50% male and 50% female). All patients underwent microbiological and immunological (determination of the level of CD3+, CD3+CD4+, CD3+CD8+, CD19+, CD45RO+ peripheral blood lymphocytes) examinations before vaccine administration and after 12 months. RESULTS: Immunization with PCV13 leads to a statistically significant decrease in the carriage of Streptococcus pneumoniae 1 year after vaccination (p=0.012). After 1 year after the administration of PCV13, the patients showed a statistically significant increase in the total number of T-lymphocytes, T-helpers, and cytotoxic T-lymphocytes in comparison with pre-vaccination levels. A statistically significant increase in the level of CD45RO+ lymphocytes was found 1 year after the administration of PCV13 (p0.0001). S. pneumoniae was found on the mucous membrane of the posterior pharyngeal wall in 16% of the participants, indicating its high prevalence in HIV-infected patients. Also, representatives of enterobacteria and Candida spp. were found in smears. (22 and 15% of participants, respectively). One year after the vaccine administration, pneumococcus was isolated from 5 participants, which is statistically significantly lower than before immunization (p=0.012). After the introduction of PCV13, there is a statistically significant increase in the total number of T-lymphocytes, T-helpers and cytotoxic T-lymphocytes 1 year after immunization. However, there is no statistically significant increase in the B-lymphocyte population. In addition, PCV13 leads to the formation of immunological memory cells in HIV-infected patients. CONCLUSION: Thus, immunoprophylaxis with PCV13 in adult HIV-infected patients leads to a decrease in the carriage of S. pneumoniae, and also promotes the stimulation of the T-cell link of the immune system and stimulates the formation of immunological memory cells.

[Experience with 13-valent conjugated pneumococcal vaccine in HIV-infected patients].

AIM: Evaluate the effect of PCV13 vaccination on the composition of the microflora of the upper respiratory tract and the immune system in HIV-infected patients. MATERIALS AND METHODS: 100 patients with HIV-infection were included in the study. The patients underwent immunological examination and the collection of biomaterial from the posterior pharyngeal wall for microbiological examination. After obtaining the results of the examinations, PCV13 was intramuscularly administered. 7 days after the introduction of the vaccine, an assessment of adverse events was carried out, after 3 months, microbiological and immunological examinations were repeated. RESULTS: Immediately after the administration of PCV13, 5% of patients felt pain during the administration. Local reactions were reported in 6 patients. One participant showed a rise in temperature to 38.3C over 2 days. Before vaccination, 16 strains of S. pneumoniae were seeded in patients. 3 months after the administration of PCV13, pneumococcus was isolated in 8 patients. 3 months after immunization, the median level of populations and subpopulations of lymphocytes became higher than the pre-vaccination. DISCUSSION: Our results show high risk of pneumococcal infections in HIV-positive patients. A tendency towards a decrease in the level of S. pneumoniae carriage was revealed 3 months after the administration of PCV13. The high level of enterobacteria carriage in HIV-positive patients is noteworthy. There is a pronounced positive effect from the use of PCV13 in HIV-positive patients on cellular factors of the immune system. CONCLUSION: The use of PCV13 is a safe and effective method for the prevention of S. pneumoniae infections.