Staphylococcus aureus, a major opportunistic pathogen, is a leading cause of biofilm-related infections in clinical practice. Staphylococcal biofilms are highly resistant to antibacterial medicines and immune effector cells. The main result of our work is the discovery of nano-vesicles in the supernatant of the human neutrophil-S. aureus biofilm system. We also found that phospholipase C treatment causes complete destruction of these vesicles. While the addition of proteinase K led to a partial structural disorganization of the vesicles, DNase treatment did not influence the vesicle structure. These observations allowed us to conclude that phospholipids and proteins play a structure-forming role in the formation of these nano-vesicles. The vesicles demonstrated anti-biofilm activities when tested against Staphylococcus epidermidis (strains 178M and 328/5) biofilms, but were ineffective for S. aureus (strains 5983/2, 5663 and 18A) biofilms.

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A study of circulating immune complexes was carried out using a reaction with polyethylene glycol. The method turned out to be simple, highly sensitive and affordable for any clinical laboratory with a photoelectric colorimeter. Analysis of the survey data of 115 healthy donors, 63 patients with rheumatoid arthritis and 16 patients with systemic lupus erythematosus made it possible to establish the level of circulating immune complexes in health and disease. The circulating immune complexes were studied in patients with rheumatism and chronic tonsillitis. To assess the results of the reaction, human aggregated gamma globulin (manufactured by Kazan NIIEM) was used.