The Impact of CFTR Modulators on the Airway Microbiome and the Need for Antibacterial Therapy in Children with Cystic Fibrosis

Background . One of the main criteria for the severity of the condition of patients with cystic fibrosis is the bacterial composition of bronchial secretions; in this regard, regular monitoring of the microbial landscape and rational use of antibacterial therapy in this category of patients are necessary. The aim of the study is to assess the impact of CFTR modulators on the respiratory microbiome and the need for antibacterial therapy in children with cystic fibrosis. Materials and methods . From November 2023 to May 2024, an open prospective study compared 46 children with cystic fibrosis (ages 2–17), including 26 on elexacaftor/tezacaftor/ivacaftor and 20 without CFTR modulators. Microbial composition and antibiotic therapy use were evaluated over 6-month pre- and post-study initiation. Results . The use of CFTR modulator contributed to a decrease in the duration of ABT courses ( p = 0.000), while the absence of therapy, on the contrary, led to an increase in the duration of ABT courses ( p = 0.003). No significant differences in the frequency of detection of individual bacterial groups between the groups were found over time. A tendency toward an increase in the amount of bacterial DNA ( p = 0.099) was found in patients who didn’t take the CFTR modulator. An increase in the concentration of Enterobacteriales was found in patients without targeted therapy during 6 months of observation ( p = 0.005). Conclusion . CFTR modulator therapy significantly reduced ABT needs in cystic fibrosis children. Although no major differences in microbial detection frequencies were found, PCR identified clinically relevant bacterial colonizations: Staphylococcus aureus , Pseudomonas aeruginosa , Haemophilus influenzae .