Chronic lung infections caused by Pseudomonas aeruginosa (PA) are a major cause of morbidity and mortality in cystic fibrosis (CF) patients. In some cases effective antibiotic therapy is no longer available, with multi-drug resistant (MDR) forms of these bacteria becoming increasingly challenging to treat. Thus, new alternative means of controlling MDR PA infections are urgently needed. Bacteriophage (phage) therapy is a potential therapeutic tool for the treatment of bacterial infections. However, due to the specific nature of phages, questions have been raised about the clinical practicality of bacteriophage based products and their ability to be effective against a range of clinical isolates.

We have previously reported on the development of prototype phage mixes and shown that phages are efficacious in reducing both bacterial load and inflammation in a murine lung infection model. In this study, we have expanded the in vitro testing and developed a bacteriophage mix active against relevant clinical PA isolates collected from around the world. We demonstrated the in vivo efficacy of the new mix in a murine lung infection model as well as the suitability of nebulisation as a delivery method.