Nocardia Isolation in People with Cystic Fibrosis and Non-CF Bronchiectasis: A Multicenter Italian Study.

Background:Nocardia species are an emergent pathogen in people with CF (pwCF) or bronchiectasis. Their clinical role and management remain unclear, and their isolation is a challenge. In this paper, we describe four cases of Nocardia detection, in two pwCF and two patients with non-CF bronchiectasis or primary ciliary dyskinesia (PCD). Methods: We conducted a multicenter retrospective study, involving pwCF and non-CF people with bronchiectasis who presented with a Nocardia detection and were followed at three CF Italian centers (Florence, Verona, and Cerignola). Results:Nocardia detection was associated with clinical and radiological respiratory exacerbation and decline in lung function. In one CF patient, Nocardia was not detected in sputum cultures after starting Elexacaftor-Tezacaftor-Ivacaftor therapy. Conclusions: Managing Nocardia detection in patients with underlying lung diseases such as CF, PCD, or bronchiectasis presents significant challenges for clinicians.