Influence of the enhancers on the bacteriophages adaptation to Pseudomonas aeruginosa clinical strains

Abstract

Introduction. One of the areas of treatment of infectious patients can be considered bacteriophage therapy. It is known that phages have a high specificity, have a different level of lytic activity, and are able to pass into a state of prophage, or adapt to the circulating bacteria strain and acquire the ability to cause their lysis. The purpose of this work was to obtain highly virulent bacteriophages by adapting their moderately sensitive clones to clinical strains of P. aeruginosa. Materials and methods. The object of study was P. aeruginosa 15 strains and 13 freshly isolated clinical strains. For experimental studies used commercial preparations of bacteriophages (Microgen, Perm, Russia)). As enhancers, were used: 1- (3,4-dimethoxybenzyl) -6,7-dimethoxyisoquinoline (0.5 ml), 2.2 ', 2' ', 2' '- (4,8-di (piperidin-1 -yl) pyrimido [5,4-d] pyrimidine-2,6-diyl) bis (azanetriyl) tetraethanol (4 ml), 2- (Phenylmethyl) -1H-benzimidazole (1 ml), which previously showed the ability to synergize to activate microbial growth. Determination of sensitivity to specific bacteriophages was performed by the drip method. The adaptation process included sequential bacteriophage passages in P. aeruginosa cultures, obtaining phage filtrate and release from culture by centrifugation at 5000 rpm. Results and discussion. The total number of strains that became sensitive to phages under the action of adapted phages was 47%, and with enhancers – 67%.In 20.0 % cases, there was a slight growth of secondary colonies (grade "+++") after the 10th passage, and 2 cultures remained resistant to phages, both to the original and adapted by both methods. Conclusion. Thus, by adapting phages to clinical strains of P. aeruginosa, it was possible to increase their lytic activity by 3.5–5 times, which indicates the promise of using this method to obtain highly effective phage preparations and phagolytic vaccines.