A bacteriophage JN02 infecting multidrug‐resistant Shiga toxin‐producing Escherichiacoli: isolation, characterisation and application as a biocontrol agent in foods

Abstract

AbstractBacteriophages are increasingly considered as novel biocontrol agents against Multidrug‐resistant (MDR) Shiga toxin‐producing Escherichia coli (STEC). In this study, a virulent phage JN02 capable of infecting MDR STEC was isolated, characterised and evaluating its efficacy in reducing MDR STEC in foods. One‐step growth and stability assay showed that JN02 had a relatively short latent period (15 min), large burst sizes (69 PFU/cell), and high physicochemical stability (temperature (30–60°C), pH (2–11), 0.1%, 1% pig bile salt, biocides and food additives (100% chloroform, 0.1% acetic acid, 1% potassium sorbate). In spot tests, 18 E. coli strains were sensitive to JN02. In efficiency of plating (EOP), 4 E. coli strains were sensitive to JN02. Electron microscopy and genome sequencing showed that JN02 belongs to the family Myoviridae. Importantly, no known virulence‐associated, lysogenic and antibiotic genes were identified in the genome of JN02. Viable cell counts of MDR STEC were significantly (P < 0.05) reduced in milk (no viable counts) and beef samples (1.0–1.9 log10 CFU cm−2 reduction) when treated with JN02 at 4 °C. The results indicated that JN02 might be a new potential natural biological control agent for MDR STEC in foods.