Isolation and characterization of a novel bacteriophage SAP_01 for the biocontrol of multidrug-resistant Staphylococcus aureus.

Multidrug-resistant (MDR) Staphylococcus aureus is an emerging food safety threat because of its ability to form persistent biofilms in food-processing environments, making eradication difficult using conventional disinfectants. In this study, a novel lytic bacteriophage, SAP_01, was isolated from wastewater and evaluated for its potential as a biocontrol agent against MDR S. aureus in food-related environments. SAP_01 formed clear plaques and exhibited a tailed morphology characterized by a polyhedral head and contractile tail. The phage demonstrated rapid adsorption and productive one-step growth with a burst size of 65.15 PFU/infected cell. SAP_01 remained stable across a wide range of temperatures, pH conditions, and salinity levels. Whole-genome sequencing revealed a circular dsDNA genome of 139,217 bp with a GC content of 29.8%, the absence of toxin genes, virulence factors, and antimicrobial resistance genes. The antibiofilm activity of SAP_01 was evaluated on high-density polyethylene (HDPE) and stainless steel (SS) surfaces. Following 12 h of incubation at 37 °C, SAP_01 significantly disrupted biofilms at all tested multiplicities of infection (MOIs), achieving reductions of 2.16 log10 CFU/cm2 on HDPE and 1.92 log10 CFU/cm2 on SS at an MOI of 100. In food application tests, SAP_01 reduced MDR S. aureus populations by 1.86 log10 CFU/g in cheese and 1.62 log10 CFU/g in ham after 24 h of storage at 4 °C without altering food color or texture. These findings demonstrate that SAP_01 is a safe and effective candidate for controlling MDR S. aureus in food systems and on food-contact surfaces.