PT - JOURNAL ARTICLE AU - Charlotte Marsac AU - Laura Berdah AU - Guillaume Thouvenin AU - Isabelle Sermet-Gaudelus AU - Harriet Corvol TI - <em>A</em><em>chromobacter xylosoxidans</em> airway infection is associated with lung disease severity in children with cystic fibrosis AID - 10.1183/23120541.00076-2021 DP - 2021 Apr 01 TA - ERJ Open Research PG - 00076-2021 VI - 7 IP - 2 4099 - http://openres.ersjournals.com/content/7/2/00076-2021.short 4100 - http://openres.ersjournals.com/content/7/2/00076-2021.full SO - erjor2021 Apr 01; 7 AB - Background Despite the increasing prevalence of Achromobacter xylosoxidans lung infection in patients with cystic fibrosis (CF), its clinical pathogenicity remains controversial. The objective of this study was to evaluate the effects of this emerging bacterium on lung disease severity in CF children.Methods This case–control retrospective study took place in two French paediatric CF centres. 45 cases infected by A. xylosoxidans were matched for age, sex, CFTR genotypes and pancreatic status to 45 never-infected controls. Clinical data were retrieved from clinical records over the 2 years before and after A. xylosoxidans initial infection.Results At infection onset, lung function was lower in cases compared with controls (p=0.006). Over the 2 years prior to A. xylosoxidans acquisition, compared with controls, cases had more frequent pulmonary exacerbations (p=0.02), hospitalisations (p=0.05), and intravenous (p=0.03) and oral (p=0.001) antibiotic courses. In the 2 years following A. xylosoxidans infection, cases remained more severe with more frequent pulmonary exacerbations (p=0.0001), hospitalisations (p=0.0001), and intravenous (p=0.0001) and oral antibiotic courses (p=0.0001). Lung function decline tended to be faster in cases (−5.5% per year) compared with controls (−0.5% per year).Conclusions This case–control study demonstrates that A. xylosoxidans occurs more frequently in the patients with the worse lung disease. Further studies assessing the pathogenicity of this emerging pathogen and international treatment recommendations are warranted.The prevalence of the opportunistic pathogen Achromobacter xylosoxidans increases in patients with CF. This study shows an association between airway infection with this bacterium and more severe lung disease in children with CF. https://bit.ly/3a7ioSi