DAILY DYNAMICS OF PARTICULAR PATHOGENICITY FACTORS AND PERSISTENCE OF STAPHYLOCOCCUS AUREUS UNDER THE INFLUENCE OF EXAMETABOLITES OF ASSOCIATIVE MICROFLORA

Aim. To study the influence of associative microflora exometabolites on enzymatic activity and persistence potential of Staphylococcus aureus during a day. Materials and methods. Collection strains S.aureus ATCC 25923, Escherichia coli 35218, and Pseudomonas aeruginosa ATCC 27853 were used. Exometabolites of E.coli and P.aeruginosa were obtained from broth cultures, which were centrifugated and supernatant was separated and sterilized by addition of chloroform. Exometabolites of microorganisms-associates were mixed with nutrient broth in 1:10 ratio with subsequent addition of pure culture of S.aureus . Broth cultures of staphylococci which do not contain exometabolites were used as controls. Biorhythms of proliferative activity of microorganisms were determined using original method developed by the authors. Catalase, hemolytic, and antilysozyme activities of bacteria were determined by photometric method, whereas activity of protease — by biuretic method. Results were statistically processed by Student's test. Results. Analysis of experimental data on the influence of exametabolites of E.coli and P.aeruginosa collection strains on daily dynamics of activity of aggression and persistence enzymes of S.aureus revealed daily cycles of studied parameters and desynchronization of biorhythms. Conclusion. Use of the developed model system allows to reveal regulatory effects of associated microorganisms on biological (pathogenic) characteristics of causative agent. Bacterial interrelations are significant regulatory action on pathogenic/persistence characteristics of a pathogen which should be taken in account for pathogenic assessment of an agent during infection it caused.

Staphylococcus aureus, daily biorhythms, persistence, pathogenicity factors, associative microflora