Bio-control of O157:H7, and colistin-resistant MCR-1-positive Escherichia coli using a new designed broad host range phage cocktail

Phages are strong antibacterial agents commonly used in the food industry, especially phage cocktails that cause much stronger and more stable effects. This study aimed to identify and characterize three absolutely lytic phages of E. coli isolated from poultry farms. Phages O18-011 and EK010 were classified in the Podoviridae family, genus Kuravirus, and Phage vB_EcoM_005 was isolated classified in the Myoviridae family, genus Dhakavirus. The bacteriolytic activity of all phages was stable in an almost wide range of temperature, pH, and salt concentrations. All the three phages exhibited extensive lytic effects on a large number of E. coli strains, including O157:H7, non-O157:H7, and colistin-resistant MCR-1-positive ones. The food test results demonstrated that the cocktail of the three phages could completely and stably inhibit E. coli through the food matrix of raw chicken meat and cherry tomatoes in a way that no E. coli was recovered by the end of the 7th day. Considering the broad host range, absolutely lytic life cycle, the absence of lysogenic-associated or inappropriate genes in their genome, and proper activity in foods, the isolated phages can be introduced as ideal candidates to be further developed as E. coli bio-control agents for food production.