This prospective observational study investigated the role of specific airway microbiome community members in pulmonary exacerbations (PEx) in cystic fibrosis (CF) patients. Respiratory samples were collected at three time points: PEx onset, end of antibiotic treatment, and follow-up. Metagenomic sequencing identified 221 bacterial species. Ten species showed significant differential gene abundance across clinical states, with *Staphylococcus aureus* dominating PEx and *Streptococcus salivarius* in follow-up. The study also found a unique differentially abundant metabolic pathway in *Veillonella atypica* during follow-up compared to PEx, suggesting a potential role in improved lung function. The findings highlight the importance of bacterial metabolic potential in understanding changes in CF clinical states.

Andrea Hahn, Elizabeth Córdoba-Lanús, Gloria Pérez-Rubio, Elpis Hatziagorou, Ioana Mihaiela Ciuca, A. Burrell, H. Chaney, I. Sami, A. Koumbourlis, R. Freishtat, K.C., E.Z., G.S., A.K.