Therapeutic Potential of Staphylococcal Bacteriophages for Nasal Decolonization of Staphylococcus aureus in Mice

Abstract

Bacteriophages represent a rich and unique resource of anti-infectives to counter the global problem of antibiotic resis- tance. In this work, we assessed the bactericidal activity of two virulent staphylococcal phages, K and 44AHJD, against S. aureus isolates of clinical significance, and tested their efficacy in vivo. The phage cocktail lysed >85% of the clinical isolates tested. Both the phages were purified by ion-exchange column chromatography following propagation in bioreactors. The purity profiles of the ion-exchange purified phages were compared with those of phages purified using cesium chloride density gradient ultracentrifugation, and infectiousness of the purified phages was confirmed by plaque forming assay. The in vivo efficacy of a phage cocktail was evaluated in an experimental murine nasal colonization model, which showed that the phage cocktail was efficacious. To our knowledge, this is the first report of phage use in an in vivo model of nasal carriage.