Characterization of the phage lysin LYS176 targeting Staphylococcus aureus and its antibacterial activity in food

Lysin LYS176, derived from Staphylococcus aureus (S. aureus) bacteriophage, exerts its bactericidal effect by hydrolyzing peptidoglycan within the bacterial cell wall, leading to rapid cell lysis. Lysin LYS176 exhibited antibacterial activity against 62 strains of S. aureus and maintained strong lytic activity within the temperature range of 10-35 °C and the pH range of 4.0-11.0. However, its lytic activity decreased with increasing NaCl concentration. Additionally, LYS176 effectively degrades biofilms, inhibits and kills S. aureus, without exhibiting any cytotoxic effects on red blood cells or mammalian cells, supporting its potential ability for food-related applications. In food challenge models, LYS176 (40 μg/mL) significantly reduced S. aureus viability when applied to milk, sausages, and food-contact packaging surfaces. After treatment at 25 °C, the counts of S. aureus were decreased by 1.24, 1.93, and 5.30 log10 CFU/mL, respectively. Notably, the most pronounced bactericidal effect was observed on the food packaging model, suggesting that LYS176 performs particularly well on abiotic surfaces where biofilm formation is a concern. In conclusion, these findings demonstrate that LYS176 is a highly effective anti-S. aureus agent, combining broad-spectrum activity, favorable physicochemical stability, biofilm-degrading capacity, and excellent biosafety. These attributes underscore its strong potential as a novel antimicrobial for controlling S. aureus contamination in the food industry.