Efficacy of a phage cocktail preparation for chronic lung infection with Pseudomonas aeruginosa in mice

Pseudomonas aeruginosa is a leading cause of hospital-acquired infections, and the emergence of multi-drug resistant strains has prompted the search for alternative treatments such as phage therapy. In this study, we combined host range and genomic information to design a four-phage cocktail that effectively killed several clinical strains (79%, 23/29) of P. aeruginosa. We demonstrated that the cocktail, composed of three novel phages (PA\_ZH1, PA\_GL1, and PA\_CQ9) and one previously characterized phage (PA\_LZ7), was able to lyse P. aeruginosa both in planktonic cultures and in alginate microbeads (an in vivo-like biofilm model). Additionally, we showed that the phage cocktail administered intranasally or intraperitoneally effectively rescued mice from chronic lung infection with P. aeruginosa. Our work explores the potential use of phages as an alternative therapeutic agent against chronic lung infections caused by P. aeruginosa strains.