ВЫДЕЛЕНИЕ И БИОЛОГИЧЕСКАЯ ХАРАКТЕРИСТИКА ЛИТИЧЕСКИХ БАКТЕРИОФАГОВ, АКТИВНЫХ В ОТНОШЕНИИ ESCHERICHIA COLI, ВЫДЕЛЕННОЙ ОТ БРОЙЛЕРНЫХ ЦЫПЛЯТ

The spread of multidrug-resistant Escherichia coli strains in industrial poultry production limits the effectiveness of antibiotic therapy and increases interest in the use of lytic bacteriophages as alternative biocontrol agents. The aim of this study was to perform a genomic characterization of the multidrug-resistant Escherichia coli isolate P47-G2 and a biological characterization of the lytic bacteriophage БФ-009/1 (BF-009/1), isolated from the production environment of a poultry farm. Whole-genome sequencing of E. coli strain P47-G2 was performed on the Illumina MiSeq platform, followed by analysis of antibiotic resistance and virulence genes. The bacteriophage was isolated from boot swab samples by the enrichment method. Its host range was investigated, with spot-test results confirmed by the double agar overlay method (plaque assay); the optimal multiplicity of infection (MOI), bactericidal activity, and thermal and pH stability were also determined. Thirteen acquired antibiotic resistance genes, including mcr-1.1, as well as 105 virulence genes, were identified in the E. coli P47-G2 isolate. Productive lytic infection by bacteriophage БФ-009/1 was confirmed only against the original host strain P47-G2, whereas the weak lysis zones observed for five heterologous isolates in the spot test were not confirmed by the plaque assay (EOP = 0). The optimal multiplicity of infection was MOI = 0.001, providing the maximal phage progeny yield ((5.10 ± 1.53) × 10⁹ PFU/mL). The phage retained infectivity after 30-minute exposure at 24–40 °C and across a pH range of 3–11. The obtained results indicate high strain specificity, pronounced lytic activity, and physicochemical stability of bacteriophage БФ-009/1. The isolated phage is of interest as a potential component of polyvalent phage preparations for the control of multidrug-resistant E. coli in industrial poultry production; however, further investigation as part of phage cocktails is required.