Development and characterization of endolysin SALys78925 with antimicrobial activity against Streptococcus agalactiae
Year: 2025
Type: article
Abstract: Streptococcus agalactiae is one of the pathogens in bovine mastitis, which contributes to substantial economic losses in the dairy industry. Endolysins are bacteriophage-encoded peptidoglycan degrading hydrolases, and they have become a novel weapon for selective elimination of target bacteria. This study aimed to identify endolysin with specific lytic activity against S. agalactiae, characterize the endolysin SALys78925, and evaluate its efficacy against related pathogens. The whole genome sequence of S. agalactiae strain was obtained from the National Center for Biotechnology Information database, and the putative gene for SALys78925 was retrieved from their genomes. SALys78925 was overexpressed in Escherichia coli BL21 (DE3) using pET system. The optimal conditions of SALys78925 were determined by assessing lytic activity under various ranges of pH, NaCl concentration, temperature, metal ions, and dosage. In silico analysis revealed that SALys78925 possesses a modular structure that comprises an N-terminal enzymatically active domain (Peptidase_M23) and a C-terminal cell wall binding domain (Zoocin A target recognition domain). SALys78925 exhibited maximal lytic activity against S. agalactiae KCCM 40417 at pH 9.0 and 37℃, but the activity decreased in a salt dose-dependent manner. The addition of Mn²⁺ enhanced SALys78925 activity, whereas Zn²⁺ reduced it by approximately 80%. Antimicrobial spectrum analysis revealed that SALys78925 exhibited varying degrees of lytic activity against multiple bacterial species, demonstrating potent lysis of S. agalactiae and lysis of Streptococcus parauberis and Enterococcus faecalis. These findings suggest that SALys78925 could be a promising candidate for preventing bovine mastitis in the dairy industry and beyond, offering a potential alternative to conventional antimicrobial treatments.
Authors: Sohyeon Yoon, Joonbeom Moon, Hanbeen Kim, Jakyeom Seo
Institutions: Pusan National University, University of British Columbia
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $383
OpenAlex ID: W4410215807