SMALL BUT MIGHTY: CHARACTERIZATION OF VB_SPY_7, A LYTIC PHAGE TARGETING STREPTOCOCCUS PYOGENES.

The emergence of antibiotic-resistant pathogens necessitates alternative therapies for treating microbial infections, especially in the oral cavity and upper respiratory tract. Our team has developed Phage Pastilles, a controlled-release formulation containing bacteriophages that target common pathogens, including Streptococcus pyogenes, Streptococcus salivarius, Staphylococcus aureus, Enterococcus faecalis, and E. coli. These pastilles incorporate eucalyptus oil and serve as a reservoir for gradually releasing bacteriophages, enhancing local therapeutic impact. This study focuses on the characterization of a novel lytic bacteriophage, vB_SPY_7, specifically targeting S. pyogenes which was incorporated into phage pastilles. Phage vB_SPY_7, isolated from wastewater, underwent host range analysis, plaque assays, adsorption kinetics, growth curve studies, electron microscopy, and whole-genome sequencing. Genomic analysis revealed that vB_SPY_7 is a member of the unclassified Caudoviricetes, with a 35,679 bp genome and 46 predicted ORFs, including essential structural and metabolic genes. Sequence analysis and biological characterization have demonstrated that vB_SPY_7 is a viable candidate for therapeutic use, and it is highly active when combined in a sustained-release format like Phage Pastilles.