Resolution of acute rejection in a bilateral double-lung transplanted cystic fibrosis patient following phage intervention.

Background: Antimicrobial resistance is a major threat to human health worldwide, requiring investigation into alternative therapeutics such as phage therapy. Phages have been used to treat numerous multidrug-resistant infections recently, particularly in people with cystic fibrosis (CF) who are predisposed to infection from Pseudomonas aeruginosa. Case Summary: Here, we report the use of phage therapy to treat a chronic P. aeruginosa infection in a 44-year-old woman with CF who underwent bilateral lung transplantation. This individual experienced acute rejection and deteriorating lung function, possibly worsened as a consequence of a P. aeruginosa infection. Phage therapy using phage vB_Pae_10 was administered via nebulizer alongside standard antimicrobials in two 10-day courses. Clinical and microbiological assessments indicated an initial reduction in bacterial load along with an improvement in lung function. Phage therapy was well-tolerated with no adverse events reported. The patient showed sustained clinical improvement, including mucus clearance, enhanced pulmonary function, and resolution of acute rejection. Conclusion: This case underscores the potential of phage therapy to complement traditional treatments in managing chronic bacterial infections in CF patients, though further studies are needed to optimize treatment protocols and understand the role of phages in modulating the bacterial population.