Bacteriophage Cocktail and Microcin-Producing Probiotic Escherichia coli Protect Mice Against Gut Colonization With Multidrug-Resistant Escherichia coli Sequence Type 131

Non-antibiotic measures are needed to reduce the rate of infections due to multidrug-resistant organisms (MDROs), including by eliminating the commensal reservoir that underlies such strains' dissemination and leads to recurrent infections. Here, we tested a cocktail of pre-selected bacteriophages and an engineered microcin C7-producing probiotic Nissle-1917 strain for their ability to reduce gut colonization by an strain from sequence type 131 (ST131)- 30R, which is the major clonal group of MDROs among extraintestinal clinical isolates. Although the bacteriophage cocktail was highly effective against ST131- 30R strains both and in a murine model of subcutaneous sepsis, it was only weakly and transiently effective against gut colonization by the target ST131- 30R strain (0.5 log decrease on + 1: