Characterization of <i>Escherichia</i> Phages Targeting Swine Colibacillosis as Potential Biosanitation and Therapeutic Agents

Background: The escalating antibiotic resistance necessitates alternative strategies like bacteriophages, utilized in livestock for growth promotion and infectious disease treatment. To select promising phage candidates, this study aimed to characterize Escherichia phages with potential against swine-associated Escherichia coli . Methods: Four E. coli phages were characterized for morphology, efficiency of plating, temperature stability, tolerance of simulated gastric fluid, long-term storage in various solutions, and lytic activity of individual and combined phages against pathogenic E. coli in tryptic soy broth and simulated intestinal fluid. Results: All phages exhibited infectivity and stability across 4°C–45°C, with varying sensitivity to low pH. The phages maintained stability in culture medium and select buffers at 4°C for at least 52 weeks. All phages exhibited significant lytic activity, with the cocktail showing enhanced reduction in certain conditions. Conclusion: These four Escherichia phages demonstrate potential as biosanitation agents for swine housing and biocontrol strategies against swine colibacillosis, warranting further in vivo investigation.