[Cellulitis due to Achromobacter xylosoxidans during bortezomib therapy for multiple myeloma]

Achromobacter xylosoxidans (A. xylosoxidans) is a non-fermentative gram-negative rod. This organism is reportedly a causative pathogen of bacteremia mainly in patients with hematological disorders. However, only one case of cellulitis due to A. xylosoxidans associated with hematological malignancy has been reported. An 80-year-old man developed cellulitis and subsequent bacteremia due to A. xylosoxidans during bortezomib therapy for multiple myeloma. Although his condition was serious enough to require intensive care, he fully recovered with appropriate antimicrobial agents and supportive care. The isolate was broadly resistant to antimicrobial agents, including cefepime, amikacin, and ciprofloxacin. Therefore, the identification and selection of appropriate antimicrobial agents were considered to have contributed to the successful outcome in this case. Physicians should recognize A. xylosoxidans as a possible pathogen causing cellulitis and secondary bacteremia, as well as being aware of its broad resistance to antimicrobial agents.