Antibacterial efficacy of recombinant phage lysin JD007-LY01 against Staphylococcus aureus in food matrices

Bacteriophage endolysins can specifically bind to and efficiently lyse host bacteria, and therefore considered promising alternatives to antibiotics. Natural endolysins, however, often have limitations such as a narrow lytic spectrum or low lytic activity, which restrict their broader application in food antibacterial control. In this study, a recombinant endolysin JD007-LY01 with a stable protein structure was constructed by fusing the binding domain of the native endolysin LY01 with the lytic domain of the exogenous endolysin JD007. Experimental results showed that JD007-LY01 lysed all Staphylococcus aureus strains and exhibited a broader lytic spectrum than LY01. The recombinant enzyme displayed optimal activity at pH 6-8 and maintained high activity at temperatures between 4°C and 40°C. In artificially contaminated milk and pork models, JD007-LY01 produced moderate reductions in viable methicillin-resistant S. aureus (MRSA) counts. It also reduced biofilm-associated cell counts on polystyrene and stainless steel surfaces. Collectively, these results indicate that JD007-LY01 exhibits improved lytic activity and a broader spectrum compared with LY01, supporting the feasibility of domain recombination as a strategy to enhance certain antibacterial properties of endolysins.