Personalized inhaled bacteriophage therapy for treatment of multidrug-resistant Pseudomonas aeruginosa in cystic fibrosis.

Bacteriophage (phage) therapy, which uses lytic viruses as antimicrobials, is a potential strategy to address the antimicrobial resistance crisis. Cystic fibrosis, a disease complicated by recurrent Pseudomonas aeruginosa pulmonary infections, is an example of the clinical impact of antimicrobial resistance. Here, using a personalized phage therapy strategy that selects phages for a predicted evolutionary trade-off, nine adults with cystic fibrosis (eight women and one man) of median age 32 (range 22-46) years were treated with phages on a compassionate basis because their clinical course was complicated by multidrug-resistant or pan-drug-resistant Pseudomonas that was refractory to prior courses of standard antibiotics. The individuals received a nebulized cocktail or single-phage therapy without adverse events. Five to 18 days after phage therapy, sputum Pseudomonas decreased by a median of 104 CFU ml-1, or a mean difference of 102 CFU ml-1 (P = 0.006, two-way analysis of variance with Dunnett's multiple-comparisons test), without altering sputum microbiome, and an analysis of sputum Pseudomonas showed evidence of trade-offs that decreased antibiotic resistance or bacterial virulence. In addition, an improvement of 6% (median) and 8% (mean) predicted FEV1 was observed 21-35 days after phage therapy (P = 0.004, Wilcoxon signed-rank t-test), which may reflect the combined effects of decreased bacterial sputum density and phage-driven trade-offs. These results show that a personalized, nebulized phage therapy trade-off strategy may affect clinical and microbiologic endpoints, which must be evaluated in larger clinical trials.