Patient #13, a 10-year-old female diagnosed with cystic fibrosis, who was admitted to the hospital for CF exacerbation with an Achromobacter xylosidans infection resistant to all available antibiotics. The patient was initially treated with the experimental antibiotic cefiderocol and 17 days later she began her phage therapy. During the first 5 days of phage therapy, the patient received both cefiderocol and phage. On the 5th day of the joint treatment the antibiotic regimen was stopped, and phage therapy continued. The patient received a single phage for therapy via IV with a titer of 2.35×10^9 PFU/mL and was released from hospital with significant clinical improvement.