VEB-1 in Achromobacter xylosoxidans from Cystic Fibrosis Patient, France

A (formerly Alcaligenes) xylosoxidans is a newly emerging microorganism isolated with increased frequency from the lungs of patients with cystic fibrosis (CF), but information about its clinical relevance is limited (1). A. xylosoxidans is innately resistant to many antimicrobial drugs (2), except piperacillin, piperacillintazobactam, and imipenem, and moderately susceptible to ceftazidime (45% of susceptible isolates), which is widely used to treat infection due to Pseudomonas aeruginosa (3,4). The mechanisms involved in cases of high-level resistance to ceftazidime have not been described for A. xylosoxidans. Possible mechanisms for ceftazidime resistance among gram-negative bacilli are alterations in outer membrane proteins, overproduction of cephalosporinase, or production of an extended-spectrum β-lactamase (ESBL). ESBLs are enzymes distributed worldwide (5) that hydrolyze oxyimino-cephalosporins and monobactams and are susceptible to β-lactamase inhibitors such as clavulanic acid and tazobactam. We report on the isolation from a CF patient of A. xylosoxidans that produced the VEB-1 ESBL. This is the first report of ESBL production in A. xylosoxidans and the first report of a VEB-1–producing isolate from a CF patient.