Lastovetska L. O., Maslak V. I., Kalinichenko O. O., Potochilova V. V., Rudnieva K. L., Iungin O. S.

MICROBIOLOGY

Scentific article

Today one of the most common and severe pathogens in hospital environments is S. aureus. Pathogenesis of most orthopedic infections is associated with biofilms formation. Biofilms are a mode of bacterial growth helped microbial community to show signs of a multicellular organism. The ability of staphylococci to form biofilms complicated the treatment of infection and often turns the process into chronic stage. One of the effective agents currently used to treat S. aureus-associated infections is the macrolide antibiotic azithromycin (AZM). The aim of the study was to evaluate the effect of azithromycin on S. aureus biofilms used the example of a collection strain and clinical isolates from the contents of chronic wounds of Ukrainian patients. Materials and methods. The ATCC strain S. aureus 25923 clinical isolates S. aureus 1536 and 190 were used in this study. Clinical cultures were isolated and identified in Kyiv Regional Clinical Hospital (Kyiv). antibiotic resistance and biofilm formation was determined using classical methods (minimal inhibitory concentrations method and MIC Test Strips according to EUCAST and crystal violet assay). Results. MICs was shown for planktonic and biofilm forms, as well as cell survival rate and adhesion levels concentration range of azithromycin 0-32 μg/ml. MICs for S. aureus biofilms was 32 μg/ml, which is several times higher than for planktonic cells. It was shown that adhesion level of hospital isolates increased with increasingof antibiotic concentration. This fact could be explained by the phenomenon of «coordinated cell death» idea. A decrease in cell survival rate was also demonstrated for these concentration of AZM. Conclusions. The differentiated effect of AZM on ATCC strain and S. aureus clinical isolates shold be taken into account according to the importance of devepolment adequate treatment strategies for S. aureus-associated infections and determining MICs for planktonic and biofilm modes of bacterial growth.

S. aureus, biofilms, azithromycin, linical isolates.

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«Bulletin of problems biology and medicine» Issue 4 (162), 2021 year, 247-250 pages, index UDK 579.61

10.29254/2077-4214-2021-4-162-247-250