Evaluate antibacterial activity of an experimental mixture of phages, belonging to several well-studied species.The study was carried out using a group of 55 clinical Pseudomonas aeruginosa strains of various origins,- 4 mono-species mixtures of 32 virulent bacteriophages (species phiKZ-, phiKMV-, phiPBl-, PaP3-like phages) and 2 novel phages, phiMK (species PaK-P2) and phiPerm5. Activity of preparations from mono-species mixtures of bacteriophages ofvarious species were compared with activity of 3 commercial mixtures. Standard methods of study of bacteriophages were used: determination of lytic activity by seeding onto bacterial lawns of P. aeruginosa, restriction analysis of phage DNA for confirmation of their be- longing to certain species.Cumulative activity of 6 mono-species mixtures of virulent phages was shown to be similar to lytic activity of commercial therapeutic mixtures used against P. aeruginosa infections. 54 of 55 strains of clinical isolates of P: aeruginosa showed sensitivity to experimental mixtures composed of mono-species mixtures of bacteriophages. 53 strains were lysed by commercial preparations. Wherein the possibility of accidental inclusion of moderate -bacteriophages in the experimental mixture is excluded.A possibility of creation of highly active therapeutic antibacterial preparations against P. aeruginosa using mono-species mixtures of 6 species of lytic bacteriophages is shown Use of such a mixture in therapy of lung infections reduces the risk of emergence of bacterial strains with increased virulence and patho- genicity during prolonged administration.
