AUTHOR=Lu Zhongjing , Marchant John , Thompson Samantha , Melgarejo Henry , Ignatova Dzhuliya , Kopić Sandra , Damaj Rana , Trejo Hedy , Paramo Rodrigo , Reed Ashley , Breidt Fred , Kathariou Sophia 

TITLE=Bacteriophages Isolated From Turkeys Infecting Diverse Salmonella Serovars

JOURNAL=Frontiers in Microbiology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.933751

DOI=10.3389/fmicb.2022.933751

ISSN=1664-302X

ABSTRACT=Salmonella is one of the leading causes of foodborne illnesses worldwide. The rapid emergence of multidrug-resistant Salmonella strains has increased global concern of salmonellosis. Recent studies have showed that bacteriophages (phages) are novel and most promising antibacterial agents for biocontrol in foods because phages specifically kill target bacteria without affecting other bacteria, do not alter organoleptic properties or nutritional quality of foods, and are safe and environmentally friendly. Due to the vast variation of Salmonella serotypes, large numbers of different and highly virulent Salmonella phages with broad host ranges are needed. This study isolated 14 Salmonella phages from turkey fecal and cecal samples. Six phages (205, 206, 207, Ent, Mont, and 13314) were selected for characterization. These phages were from all three families in the Caudovirales order. Sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) revealed that each phage had a unique structural protein profile. Each phage had a distinct host range. 207 and Ent are both siphophages. They shared eight hosts including seven different Salmonella serovars and one Shigella sonnei strain. These two phages showed different restriction banding patterns generated through EcoRI or HindIII digestion, but shared three bands from EcoRI digestion. Ent displayed the broadest and very unusual host range infecting 11 Salmonella strains from nine serovars and three Shigella strains from two species, and thus was further characterized. One-step growth curve revealed that Ent had a short latent period (10 min) and a relatively large burst size (100 PFU/infected cell). Ent and its host showed better thermal stabilities in tryptic soy broth than in saline at 63C or 72C. In the model food system (cucumber juice or beef broth), Ent infection (regardless of multiplicity of infections of 1, 10, and 100) resulted in more than 5 log10 reduction in Salmonella concentration within 4 or 5 h. Such high lytic activity combined with its remarkably broad and unusual host range and good thermal stability suggested that Ent is a novel Salmonella phage with a great potential to be used as an effective biocontrol agent against diverse Salmonella serovars in foods.