A Dynamic Method for Broad-Spectrum Bacteriophage Cocktail Formulation Against Poultry-Associated Salmonella enterica

Phage (New Rochelle). 2020 Jun 1;1(2):109-117. doi: 10.1089/phage.2020.0002. Epub 2020 Jun 16.

Abstract

Background: Poultry products are the largest food category linked to salmonellosis in Canada. Bacteriophages (phages) have been proposed as a novel antimicrobial in the poultry industry due to their documented ubiquity, efficacy, and safety benefits. Materials and Methods: A library of 78 lytic phages was rapidly screened against 50 prominent poultry-associated Salmonella enterica isolates procured from British Columbia, Canada. Results: A phage cocktail was successfully formulated using only three sewage-isolated phages (SE4, SE13, and SE20) to achieve broad-spectrum antimicrobial efficacy across all S. enterica serovars. Highly promising phages were also characterized using one-step growth curves and transmission electron microscopy. Conclusion: Relative host efficiency is a new agar-based semiquantitative metric developed here for the rapid comparison of different phages against a panel of known bacterial targets.

Keywords: Salmonella enterica; bacteriophage cocktail; poultry; relative host efficiency.