Increased frequency of non-aeruginosa Pseudomonas species isolation from the airways of people with cystic fibrosis after initiating Elexacaftor/Tezacaftor/Ivacaftor treatment

<title>Abstract</title> <p> The introduction of elexacaftor/tezacaftor/ivacaftor (ETI) has significantly improved outcomes in people with cystic fibrosis (pwCF), although its impact on non- <italic>aeruginosa Pseudomonas</italic> species (NAPs) remains poorly understood. We retrospectively analysed respiratory cultures from 417 pwCF attending three Italian CF centres before and after ETI initiation. Twenty patients (4.8%) had at least one NAPs-positive culture after ETI, compared with one patient before treatment ( <italic>p</italic>  &lt; 0.001). Fifteen different species were identified, mainly belonging to the <italic>Pseudomonas fluorescens</italic> and <italic>P. putida</italic> groups. ETI may alter the airway microbiota, increasing NAPs detection. Further studies are needed to determine their clinical significance and guide management. </p>