Characterization and genome analysis of the novel virulent Burkholderia phage Bm1, which is active against pan-drug-resistant Burkholderia multivorans

The escalating challenges of antibiotic resistance in bacterial pathogens have necessitated the exploration of alternative therapeutic strategies. Among these, bacteriophage therapy has regained attention as a promising approach to combat multidrug-resistant bacteria. Bacteriophages are viruses that infect and lyse specific bacterial strains, making them attractive candidates for targeted antimicrobial treatment. Burkholderia multivorans, a Gram-negative bacterium, is known to cause opportunistic infections, particularly in individuals with a compromised immune system or with cystic fibrosis. The prevalence of antibiotic-resistant Burkholderia strains has raised concerns about treatment options. In this study, we characterized the Burkholderia phage Bm1, a virulent bacteriophage isolated from an environmental source. Electron microscopy revealed that Bm1 phage particles have myovirus morphology, with an icosahedral head of 72 nm in diameter and a contractile tail of 100 nm in length and 18 nm in width. The genome of phage Bm1 consists of a double-stranded DNA of 67,539 bp with a terminal repeat region at each end. Comparative analysis indicated that the closest relative of phage Bm1 is Burkholderia phage BCSR129, with a calculated VIRIDIC identity of 57.7%. The apparent absence of an integrase gene suggests that the Burkholderia phage Bm1 has a strictly lytic life cycle.