Stability Study of Four Isolated E. coli O157 Phages and Influence of Various Carriers on Their Cocktail effectivity

Background: Escherichia coli O157 is a pathogen that induces severe gastrointestinal illnesses with potentially life-threatening consequences, posing a threat to public health. Phage therapy, which employs bacteriophages to target and destroy bacteria specifically, is a potential alternative or complement to traditional antibiotic treatment. Objectives: This study employed the biocontrol of the most resistant E. coli O157 using a phage cocktail of four lytic phages. Methodology: This study involved detection, isolation, and characterization of four bacteriophages targeting an E. coli O157 isolate and the effect of three different carriers on their stability. Results: Plaque morphology and TEM micrographs revealed that two phages are from Myoviridae, one is from Siphoviridae, and the other is from Podoviridae. Conclusion: Our findings indicated that the phage cocktail demonstrated higher stability till 80ºC and 15% NaCl, and its viability was recorded in both acidic and alkaline conditions. Phage cocktail was mixed with three carriers, royal jelly, sorbitol, and trehalose in 1:1 (V: W%). By studying the stability of all formulas over time, trehalose was introduced as the best carrier, making it the preferred choice for application.