Isolation and characterization of Enterococcus phages vB_EfaS_785CC and vB_EfaS_785CS

Phage therapy offers a promising alternative to antibiotics, with lysin capacity being a key determinant of therapeutic efficacy. This study isolated two Enterococcus faecalis phages, vB_EfaS_785CC and vB_EfaS_785CS, from aquatic market sewage. They are classified as species LY0322 in the genus Efquatrovirus of the class Caudoviricetes, had rapid lysis and potent antibacterial activity against multidrug-resistant enterococci, highlighting their biocontrol potential. Despite a 99.95% nucleotide sequence similarity, these two phages display significant phenotypic differences in lysis ability. Comparative genomic analysis indicates that these lytic differences stem primarily from variable-length homopolymer-tracts in their genomes, which induce coding mutations affecting tail proteins and DNA metabolism genes, thus influencing lysis capacity. The findings guide future research in enhancing phage lytic potential.