This Gut Ain't Big Enough For the Both of Us

To date, antibiotics are the most common method to eradicate bacteria. However, due to the extensive use of them, many bacteria have acquired mechanisms to resist a wide range antibiotics. One alternative approach of treatment is by bacteriophage therapy, viruses that infect and kill bacteria. The drawback of this therapy is that bacteria, in a similar fashion, develop resistance to phage infection as well. In this study, we hypothesized that a competition between bacteriophage resistant bacteria and antibiotic resistant bacteria, in the presence of bacteriophage, will lead to eradication of the antibiotic resistant bacterial strain. We aimed to eradicate Vancomycin Resistant Enterococci, 'VRE', with bacteriophages. To overcome phage infection resistance, we added a competing Enterococcal strain that occupied the niche and hindered the ability of the VRE strain to recover after infection. The competing strain was taken from a healthy microbiome of a human gut. All experiments were performed in mice that were treated with broad spectrum antibiotics for three days and then were colonized with VRE by oral gavage . Before adding the competing bacteria and the bacteriophages to the mice, we exposed the competing bacteria to the bacteriophage therapy in vitro, rendering it immune to phage infection . Thus, when the bacteriophages were added to mice, only the VRE strain died. This treatment proved to be more efficacious than just bacteriophage alone but did not completely eradicate the antibiotic resistant bacteria.