Characterization of a lytic phage KFS-EC3 infecting multiple foodborne pathogens

The purpose of this study was to characterize lytic and genomic properties of phage KFS-EC3 used as a biocontrol agent. The morphology of KFS-EC was observed by transmission electron microscopy (TEM). The polyvalent bactericidal activity of KFS-EC3 was determined against various host bacteria by enumerating bacterial number after phage treatment at multiplicities of infection (MOIs) of 0.001, 0.1, and 1.0 for 4 h. Finally, whole-genome sequencing was performed and annotated to identify its lytic property, safety, and novelty. TEM observation revealed that KFS-EC had morphology of myophage with an icosahedral head and contractile tail. In addition, KFS-EC3 could reduce E. coli, The Salmonella, Shigella sonnei, and their bacterial cocktail by ~3 log CFU/mL, even at the lowest MOI of 0.001. The genomic analyses revealed that KFS-EC3 consisted of 167,440 bp and 151 functional genes, without any genes related to antibiotic resistance, virulence, allergenicity, and lysogenicity. Among the genes involved in host cell lysis, endolysin, holin, and a receptor binding protein were identified. Furthermore, KFS-EC3 was classified into a new phage of the Tequatrovirus genus in the Myoviridae family. In conclusion, lytic and safe phage KFS-EC3 with a broad host range can be used as a biocontrol agent to control foodborne pathogens.