A case of renal abscess and bacteremia caused by Burkholderia pseudomallei that was first unidentifiable by matrix-assisted laser desorption ionization-time of flight mass spectrometry in a Japanese-man.

Melioidosis, an infectious disease caused by Burkholderia pseudomallei, is endemic in specific regions, including Southeast Asia and Northern Australia. In Japan, where no autochthonous has been reported to date, melioidosis is a rare infectious disease. Herein, we report a case of melioidosis in a 68-year-old Japanese man with renal abscess and bacteremia, but without pneumonia. The patient presented to our hospital and was admitted for fever and chills that have persisted for two months. It was speculated that he was infected in Thailand, where his family lives because he shuttled between Thailand and Japan. Blood cultures on admission identified Burkholderia species; however, the species was unidentifiable by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Further re-examination, including culture, loop-mediated isothermal amplification, and multiplex polymerase chain reaction methods, finally identified Burkholderia pseudomallei. We treated the patient with intravenous ceftazidime for four weeks. In addition to the antibiotics administration, puncture drainage of the renal abscess was performed, and he gradually became afebrile. Intravenous ceftazidime was switched to oral sulfamethoxazole/trimethoprim on post-admission day 32, and he was discharged. After five months of oral sulfamethoxazole/trimethoprim, no recurrence was observed one year after discharge. To diagnose melioidosis, especially in non-endemic areas, a precise and thorough understanding of its epidemiology, presentation, and identification methods is necessary.