Optimized phage therapy for Brucella infection

Brucellosis is a zoonotic infection caused by Brucella species. Two species, B. abortus and B.melitensis, are select agents and considered potential bioweapons, and there are no approvedvaccines for use in humans. Approved vaccines do exist for livestock; however, they are only60-70% effective, are infectious to humans, sometimes abortogenic, and the smooth vaccinecan convolute diagnostic serology. Treatment of humans with brucellosis is complicated,requiring the administration of two antibiotics for extended periods of time. Such long-termantibiotic use has negative consequences upon the microbiome, now appreciated as critical inmaintaining immune homeostasis and gut health. Development of antibiotic resistance is also aconcern. As such, there is a clear need for new approaches for treatment of brucellosis, and thisextends to a number of other bacterial diseases. We found that stimulation of innate immunitycan reduce Brucella burden in the mouse model. In combination with other therapies, thistreatment could eliminate infection. Bacteriophage (phage) therapy is a novel, highly specificalternative to antibiotics. We propose to use Brucella-specific phages, in combination withinnate immune stimulation, as a novel countermeasure for brucellosis. Brucella can replicateintracellularly, sequestered away from phages. Thus, we will also encapsulate phage inliposomes for enhanced uptake into cells. We hypothesize that Stimulation of the innateimmune system together with phage therapy, with or without liposome delivery, willresult in synergistic and successful protection from Brucella infection. We will assess theeffects of Brucella phages on Brucella replication in macrophages in vitro. The phages will becombined with innate immunostimulation, and encapsulated into liposomes. We will assess theeffects of the novel phage preparations in the mouse model of brucellosis. At the completion ofthese studies, we will have proof of principle for an alternative treatment for brucellosis andpossibly other diseases caused by intracellular bacterial pathogens.!