Simultaneous Control of Staphylococcus aureus and Bacillus cereus Using a Hybrid Endolysin LysB4EAD-LysSA11
Department of Food and Animal Biotechnology, Seoul National University, Seoul 08826, Korea
Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, Korea
Department of Food Science and Technology, Seoul National University of Science and Technology, Seoul 01811, Korea
Division of Applied Food System, Food Science & Technology, Seoul Women’s University, Seoul 01797, Korea
Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea
Center for Food and Bioconvergence, Seoul National University, Seoul 08826, Korea
Author to whom correspondence should be addressed.
Antibiotics 2020, 9(12), 906; https://doi.org/10.3390/antibiotics9120906
Received: 24 November 2020 / Revised: 8 December 2020 / Accepted: 11 December 2020 / Published: 14 December 2020
(This article belongs to the Special Issue Development of Bacteriophage Derived Lysins and Depolymerases for Therapeutic Purposes in Combating Bacterial Pathogens)
Bacteriophage endolysins have attracted attention as promising alternatives to antibiotics, and their modular structure facilitates endolysin engineering to develop novel endolysins with enhanced versatility. Here, we constructed hybrid proteins consisting of two different endolysins for simultaneous control of two critical foodborne pathogens, Staphylococcus aureus and Bacillus cereus. The full-length or enzymatically active domain (EAD) of LysB4, an endolysin from the B. cereus-infecting phage B4, was fused to LysSA11, an endolysin of the S. aureus-infecting phage SA11, via a helical linker in both orientations. The hybrid proteins maintained the lytic activity of their parental endolysins against both S. aureus and B. cereus, but they showed an extended antimicrobial spectrum. Among them, the EAD of LysB4 fused with LysSA11 (LysB4EAD-LyaSA11) showed significantly increased thermal stability compared to its parental endolysins. LysB4EAD-LysSA11 exhibited high lytic activity at pH 8.0–9.0 against S. aureus and at pH 5.0–10.0 against B. cereus, but the lytic activity of the protein decreased in the presence of NaCl. In boiled rice, treatment with 3.0 µM of LysB4EAD-LysSA11 reduced the number of S. aureus and B. cereus to undetectable levels within 2 h and also showed superior antimicrobial activity to LyB4EAD and LysSA11 in combination. These results suggest that LysB4EAD-LysSA11 could be a potent antimicrobial agent for simultaneous control of S. aureus and B. cereus.