Biological characteristics of Multidrug-Resistant Proteus mirabilis Bacteriophage and Its Antibacterial Effect on Chicken Breast Meat

Objective: To isolate a bacteriophage infecting multidrug-resistant Proteus mirabilis, determine its biological properties and evaluate its antibacterial effect on chicken breast. Methods: The morphology of the bacteriophage was examined using transmission electron microscopy (TEM), and the multiplicity of infection (MOI), one-step growth curve, and stability were systematically assessed. The host range of the bacteriophage was assessed using the dot blot technique. Subsequently, its genome was extracted and analyzed through whole genome sequencing. Crystal violet staining and plate counting were employed to assess the ability of the phage to remove biofilms and the efficiency in removing biofilms on different materials was evaluated using the plate counting method. The antibacterial effect on chicken breast meat was measured at 4 and 25 ℃. Results: A long-tailed bacteriophage, vB_PMC-PL1, was obtained. Comprehensive genomic analysis revealed that the bacteriophage belonged to the Novosibvirus genus within the Demerecviridae family. Notably, the analysis did not identify any genes associated with virulence, antibiotic resistance, or integrase activity. Phage vB_PMC-PL1 exhibited an optimal MOI of 0.1, an incubation period of 20 min and a burst size of 106 PFU/cell. The titer of vB_PMC-PL1 was stable at pH 3–11 and temperatures ranging from 4 to 50 ℃. The host range test showed that vB_PMC-PL1 could lyse not only Proteus mirabilis but also Proteus vulgaris. vB_PMC-PL1 effectively eradicated bacterial biofilm formed on both stainless steel and high-density polyethylene (HDPE) surfaces. At MOIs of 1 000 and 10 000, it reduced the bacterial concentration in chicken breast meat by 0.95 and 1.01 (lg(CFU/g)) after 6 h incubation at 4 ℃, and by 1.50 and 1.67 (lg(CFU/g)) after 9 h incubation at 25 ℃, respectively. Conclusion: vB_PMC-PL1 exhibited lytic activity against both P. mirabilis and P. vulgaris, demonstrating significant efficacy in disrupting P. mirabilis biofilm. This study not only enriches the Proteus bacteriophage resource library, but also provides a reference for the development of Proteus phage cocktails and the application of biological control in food safety.