Achromobacter xylosoxidans bacterial strains and characterization of bacteriophage active against them

Bacteria of the genus Achromobacter are rare pathogens that cause severe infectious diseases. Achromobacter-associated diseases are difficult to treat due to resistance to a wide range of antibiotics. Additionally, these pathogens are often identified incorrectly or late. The saprophytic nature of these bacteria also complicates the diagnosis. Due to the clinical characteristics of the diseases caused by A. xylosoxydans and the need to develop an optimal therapeutic approach, research has been going on for years and is still a hot topic. The uncontrolled and frequent use of antibiotics in the world has led to an increase in the number of microbes resistant to them. There has been interest in developing different means of controlling and treating infections caused by pathogenic bacteria. These include phage therapy as an alternative to antibiotic therapy. Phages (bacteriophages) are the largest group of viruses, and their mission is to destroy the target bacterial cell. Interest in virulent bacteriophages as antimicrobial agents is growing due to their potential applications in areas such as diagnosis, therapy, and biocontrol of bacterial infections. A prerequisite for the therapeutic use of phages is their versatile characterization. The aim of the study was to characterize Achromobacter xylosoxidans bacterial strains and the bacteriophage active against them. 17 A. xylosoxidans strains and specific bacteriophage from the collection of the molecular biology laboratory of G. Eliava Institute of Bacteriophages, Microbiology and Virology were used. During the study, we set the following tasks: determination of the sensitivity of bacterial strains to the antibiotics and bacteriophages; genotyping of strains; study of the antibacterial activity of bacteriophage of interest, i.e., the lytic spectrum; obtaining a pure line of the selected phage and determining its characteristics of the intracellular reproduction cycle; determination of the frequency of generation of phage-resistant mutant forms in the population of phage-infected bacteria; bacteriophage DNA extraction and its restriction analysis; determining the size of the bacteriophage genome and the electron-microscopic study of the morphology of the intact virion.