Achromobacter xylosoxidans in patients with primary ciliary dyskinesia

<b>Background:</b> Although <i>Achromobacter xylosoxidans (AX)</i>,a non-fermentative Gram-negative bacillus, is considered an emerging pathogen in cystic fibrosis^1,2, the extent and significance of pulmonary <i>AX</i> infections in patients with primary ciliary dyskinsia (PCD) is quite unclear². We wanted to explore and characterize the significance of <i>AX</i> infections in the Danish PCD cohort. <b>Methods:</b> We reviewed our microbiological database on samples of respiratory sputum cultures collected from the Danish PCD cohort in the period 2002-18. Since we specifically wanted to investigate the prevalence of <i>AX</i> infections all patents with at least one <i>AX</i> culture were characterized. <b>Results:</b> 4956 sputum samples were identified in 140 patients with PCD. The prevalence of <i>AX</i> was 2.5% as opposed to <i>Haemophilus influenzae</i> 29%, <i>Staphylococcus aureus</i> 14%, <i>Pseudomonas aeruginosa</i> 13%, <i>Streptococcus pneumoniae</i> 12%, <i>Moraxella catarrhalis</i> 12%, <i>Stenotrophomonas maltophilia</i> 3.5%, and <i>Aspergillus</i> 14%. Eighteen patients (7.7%) had at least one positive culture of <i>AX</i>. Five patients had only a single isolate, while 13 patients with a median(range) age of 34(2-67) years at first acquisition had 3(2-31) positive samples over a period of 14 (0-192) mos. Six of these patients were considered chronically infected but successful eradication was accomplished in all except one patient. <b>Conclusion:</b> Although pulmonary infection with <i>AX</i> occurs relatively rarely among patients with PCD it cannot be ignored, and the infection has both isolation and treatment consequences over many months to years, albeit with a good probability of eradication. Its impact on pulmonary function remains to be clarified. <b>References:</b> 1. J Cyst Fibros. 2010;9(1):51-8. 2. Chron Respir Dis. 2017;14(4):392-406.