Recurrent Achromobacter xylosoxidans bacteremia associated with persistentlymph node infection in a patient with hyper-immunoglobulin M syndrome

Achromobacter xylosoxidans (formerly Alcaligenes xylosoxidans) is a rare bu t important cause of bacteremia in immunocompromised patients, and strains are usually multiply resistant to antimicrobial therapy. We report an immun ocompromised patient with hyper-immunoglobulin M syndrome who suffered from 14 documented episodes of A. xylosoxidans bacteremia. Each episode was tre ated and resulted in rapid clinical improvement, with blood cultures testin g negative for bacteria. Between episodes, A. xylosoxidans was isolated fro m an excised right axillary lymph node, whereas the culture of the central venous catheter, removed at the same time, was negative. Multiple cultures from sputum, stool, and urine samples, as well as from gastrointestinal bio psies or environmental sources, were negative. Results from antibiotic sens itivity testing and pulsed-held gel electrophoresis suggested that a single strain of A. xylosoxidans caused the recurrent bacteremias in this patient ; this strain originated from persistently infected lymph nodes. Lymphoid h yperplasia is a prominent characteristic of hyper-IgM syndrome and may serv e as a source of bacteremia with low-pathogenicity organisms.