The abuse of antibiotics in the livestock and poultry industry has accelerated the spread of bovine-derived methicillin-resistant Staphylococcus aureus (MRSA), which not only endangers cattle health and reduces breeding efficiency but also threatens public health through the food chain. In this study, a lytic phage vB_SauL_SHZU01 targeting multidrug-resistant bovine-derived MRSA was isolated from dairy farm wastewater and systematically characterized. The phage had an icosahedral head and a long tail, belonging to the family Siphoviridae. It had an optimal multiplicity of infection (MOI) of 0.1, a short latent period of only 30 minutes, and strong infectivity. Its titer peaked at 37℃; it tolerated temperatures up to 50℃, remained infectious within pH 6-10, and showed time-dependent sensitivity to UV radiation. Whole-genome sequencing revealed that the phage contains a linear double-stranded DNA genome of 44,364 bp with a GC content of 33.6%. No antibiotic resistance genes were detected, but one anti-CRISPR protein-coding region was identified. Mouse experiments showed that 10⁸–10¹⁰ CFU of this S. aureus strain caused 100% mortality in mice, while doses ≤10⁷ CFU were non-lethal. The therapeutic effect of phage vB_SauL_SHZU01 was dose-dependent: it provided protection at ≥10⁷ PFU, achieved 100% mouse survival at 10⁸ PFU, and repaired liver, spleen, and kidney tissue damage caused by MRSA infection. In dairy product matrices, the phage effectively reduced the viable count of MRSA, and its antibacterial activity was synergistically regulated by temperature, matrix type, and MOI. In summary, phage vB_SauL_SHZU01 displays excellent lytic activity against multidrug-resistant bovine-derived MRSA. Systematic research on this phage provides a basis for understanding phage-host interactions and optimizing phage therapy, lays a technical foundation for the biological control of drug-resistant bacteria in livestock and poultry farming, and safeguards the safety of animal products and public health.

To Cite This Article: Liang Y, Wang W, Guo Y, Wang J, Tian M, Zhang H and Hao H, 2026. Bovine-derived mrsa bacteriophage vb_saul_shzu01: study on biological characteristics, genomics and dairy product applications. Pak Vet J, 46(6): 1387-1402. http://dx.doi.org/10.29261/pakvetj/2026.134