Isolation and Characterization of a Novel Thermostable Bacteriophage Targeting Multi-Drug-Resistant <em>Salmonella</em> Enteritidis

1) Background: The emergence of multidrug-resistant (MDR)-Salmonella enterica poses a major threat to global public health underscoring the urgent need for alternative therapeutic strategies where bacteriophages are a promising candidate due to their high specificity and potent ability to lyse MDR strains.2) Methods: In this study, we isolated a novel MDR-Salmonella Enteritidis-targeting bacteriophage from Lebanese sewage and characterized its host range, thermal and PH stability, and infection dynamics. Whole-genome sequencing was performed by Illumina to determine genetic features and taxonomic position.3) Results: the bacteriophage belongs to genus Jerseyvirus and Class Caudoviricetes with a 43kb dsDNA genome and 66 ORFs. It demonstrated extraordinary thermal stability, retaining infectivity after prolonged incubation at 65 °C, showed a broad host range, produced large, clear plaques, displayed rapid adsorption (&gt;97% within 3 min), a short latent period (20 min), and a burst size of ~320 PFU per cell. Genome analysis revealed no lysogeny, virulence, or resistance genes, confirming its strictly lytic nature and supporting its potential use as a biocontrol agent. 4) Conclusions: These findings identify SA01 as a novel, strictly lytic, and thermally stable bacteriophage with strong potential as a biocontrol agent against multidrug-resistant Salmonella Enteritidis, supporting its potential activity also against other Salmonella enterica serovars for future applications in food safety and biotechnology.