Bacteriophages Isolated From Turkeys Infecting Diverse Salmonella Serovars

Abstract

Salmonella is one of the leading causes of foodborne illnesses worldwide. The rapid emergence of multidrug-resistant Salmonella strains has increased global concern for salmonellosis. Recent studies have shown that bacteriophages (phages) are novel and the 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 in 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 (Φ205, Φ206, Φ207, ΦEnt, ΦMont, and Φ13314) 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. Φ207 and ΦEnt 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. ΦEnt 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. The one-step growth curve revealed that ΦEnt had a short latent period (10 min) and relatively large burst size (100 PFU/infected cell). ΦEnt and its host showed better thermal stabilities in tryptic soy broth than in saline at 63 or 72°C. In the model food system (cucumber juice or beef broth), ΦEnt infection [regardless of the multiplicity of infections (MOIs) 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 ΦEnt is a novel Salmonella phage with great potential to be used as an effective biocontrol agent against diverse Salmonella serovars in foods.

Enrichment Culture but Not Metagenomic Sequencing Identified a Highly Prevalent Phage Infecting Lactiplantibacillus plantarum in Human Feces

“…Gut-P1 showed a shorter latent time than other Lactobacillus phages ( 46 , 47 ). A shorter latent period has been positively related to the lytic activity of the phage, which suggests a stronger growth suppression ability against its hosts ( 48 ). The calculated burst size of the phage, the ratio of the total number of the released phage progeny at the end of one growth cycle to the initial count of infected bacterial cells, was approximately 1,270 phage particles per infected cell, which is close to the maximum reported for DNA phages ( 49 ).…”

Multifunctional nanoreactors with nutrient consumption and ROS generation capabilities for antibacterial and skin repair

“…The excellent antibacterial and skin repair properties, as well as the good biosafety make GOx@Cu-ZIF-8 an innovative biomaterial for antibacterial and tissue regeneration. In order to further exploit the advantages of the nanoreactor and promote its therapeutic effect, we plan to use the nanoreactor to deliver bacteriophage, a promising antibacterial and tissueregenerating agent, [35][36][37][38] in future studies.…”