Cystic fibrosis: Achromobacter xylosoxidans colonized patients have more severe respiratory disease

Background: The consequence of Achromobacter xylosoxidans colonization on the respiratory function of cystic fibrosis (CF) patients is not well known. Methods: Case-control study including six A. xylosoxidans -colonized CF patients and 11 matched uncolonized controls. FEV 1 , number of courses of antibiotics (nCA) and number of hospital admissions for respiratory reasons (nHAR) were compared in the two groups from T-3 (3 years before colonization) to T+3 (3 years after colonization). Results: nCA and nHAR were significantly higher from T-3 to T0, at T0 (colonization) and from T0 to T+3 in A. xylosoxidans -colonized patients than in controls ( p <0.05 for all parameters). Median FEV 1 at T0 ( p =0.05) and from T0 to T+3 ( p =0.03) was lower and decrease in FEV 1 from T-3 to T+3 was faster ( p =0.05) in A. xylosoxidans -colonized patients. Moreover, broncho-pulmonary aspergillosis occurred more often in A. xylosoxidans -colonized patients (p=0.003). When patients were compared to themselves over the periods T-3 to T0 against T0 to T+3, there was no difference for the variable studied, comprising respiratory function tests. Conclusions: A. xylosoxidans -colonized CF patients have inherently more severe respiratory disease than uncolonized patients. However, A. xylosoxidans colonization did not affect the evolution of respiratory function.