Impact ofAchromobacter xylosoxidansisolation on the respiratory function of adult patients with cystic fibrosis

Abstract

BackgroundThe prevalence of Achromobacter xylosoxidans lung isolation in cystic fibrosis (CF) patients has increased, but the impact on lung function is controversial. The aim of this study was to evaluate the long-term effects of A. xylosoxidans isolation on respiratory function of adult patients with CF in the first 3 years after identification of A. xylosoxidans isolation.MethodsThis was a case–control retrospective study performed at a single CF centre in Lille, France. Data for 36 patients with CF who had at least one sputum culture positive for A. xylosoxidans (Ax+) were evaluated and compared with control CF patients uninfected by A. xylosoxidans (Ax−). Respiratory function and exacerbation frequency were evaluated between 1 year prior to and 3 years after A. xylosoxidans isolation.ResultsCompared with the Ax− group, the Ax+ group had a lower forced expiratory volume in 1 s (FEV1) at baseline (median (interquartile range): 55.2% (50.6–59.8%) versus 73.8% (67.2–80.4%); p=0.005), a greater decline in FEV1 (±se) in the first year after A. xylosoxidans identification (−153.6±16.1 mL·year−1 versus −63.8±18.5 mL·year−1; p=0.0003), and more exacerbations in the first 3 years after A. xylosoxidans identification (9 (7–12) versus 7 (5–10); p=0.03). Ax+ patients co-colonised with Pseudomonas aeruginosa (n=27, 75%) had a greater FEV1 decline (p=0.003) and more exacerbations in the year after A. xylosoxidans identification (p=0.037) compared with patients colonised with A. xylosoxidans alone. Patients with chronic A. xylosoxidans isolation (n=23, 64%) had more exacerbations than intermittently colonised patients in the 3 years after A. xylosoxidans identification (p=0.012).ConclusionA. xylosoxidans isolation is associated with a decline in respiratory function in patients with CF. Chronic A. xylosoxidans isolation and P. aeruginosa co-isolation may be markers of more severe respiratory disease in Ax+ patients.

Bilateral Pneumonia in a Patient with Chronic Bronchiectasis Caused by Achromobacter xylosoxidans Subspecies denitrificans

“…xylosoxidans [4,6,8]. Our patient had chronic bronchiectasis, most likely due to a previous MAI infection.…”

“…Microscopically, A. xylosoxidans is very similar to Pseudomonas aeruginosa, which can potentially lead to lower rates of detection [8]. In patients with CF, the co-colonization of P. aeruginosa and A.…”

“…A. xylosoxidans is a relatively rare pathogen to cause respiratory disease but is more commonly found in patients with CF [8]. The reported prevalence rate of colonization in CF populations varies between 5.3% and 13.1% [8][9]. This case report describes a patient with a past medical history of chronic bronchiectasis who was diagnosed with pneumonia caused by A. xylosoxidans subspecies denitrificans.…”

“…xylosoxidans subspecies denitrificans is less commonly reported as a pathogen than the xylosoxidans subspecies [2,4]. A. xylosoxidans is a relatively rare pathogen to cause respiratory disease but is more commonly found in patients with CF [8]. The reported prevalence rate of colonization in CF populations varies between 5.3% and 13.1% [8][9].…”

Achromobacter xylosoxidansairway infection is associated with lung disease severity in children with cystic fibrosis

“…The pathogenicity of A. xylosoxidans lung infection remains controversial [ 8 – 14 ] and there is no international recommendation concerning its management. Indeed, it is actually unclear whether antimicrobial treatments directed against this emerging pathogen alter the severity of CF lung disease [ 8 – 11 ]. Therefore, we conducted a retrospective study to evaluate the effects of A. xylosoxidans airway infection on lung disease severity in CF children.…”