Shiga toxin-producing Escherichia coli and Salmonella enterica are important pathogens worldwide. Bacteriophages can be effectively used to reduce the incidence of foodborne pathogens. The host recognition systems of phages are highly specific, with the host range of a common phage being limited to the species or strain level. Here, we characterized a novel broad-host-range phage, EscoHU1, that infects several bacterial species, including E. coli and S. enterica, and evaluated its antimicrobial potential to inhibit E. coli O157:H7 and S. Typhimurium growth in food systems. The adsorption of EscoHU1 on E. coli was faster than that on S. Typhimurium; however, the one-step growth curves of EscoHU1 in both species were similar. Genomic analysis of EscoHU1 revealed that this phage has long direct terminal repeats at both ends of the genome, and phylogenetic analysis of the terminase large subunit confirmed that EscoHU1 belongs to the genus Epseptimavirus. Comparative analysis of structural proteins indicated a diversity of proteins related to the host range (receptor-binding proteins and L-shaped tail fibers). Challenge tests using beef and milk demonstrated the antimicrobial effects of EscoHU1 in inhibiting the growth of E. coli O157:H7 and S. Typhimurium in the food system. However, the antimicrobial effect of EscoHU1 on S. Typhimurium was lower than that on E. coli O157:H7. These results suggest that the novel broad-host-range phage EscoHU1 may serve as an effective antimicrobial agent to reduce food poisoning caused by E. coli O157:H7 and S. Typhimurium.
Keywords: Broad host range phage; Comparative analysis; Demerecviridae; Epseptimavirus; Phage utilization.
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