Urethrocutaneous fistula and subcutaneous abscess in the inguinal region with bacteremia caused by Bilophila wadsworthia in a Japanese patient: A case report

Bilophila wadsworthia is an anaerobic, gram-negative bacillus commonly associated with acute appendicitis. However, bacteremia is exceedingly rare. Herein, we report a case of B. wadsworthia bacteremia associated with a urethrocutaneous fistula and a subcutaneous abscess in the left inguinal region. A 75-year-old man was referred to our hospital due to persistent fever despite piperacillin treatment. The patient was diagnosed with a urethrocutaneous fistula and a subcutaneous abscess in the left inguinal region. B. wadsworthia was isolated from his blood culture and identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Subsequently, the patient underwent a four-week course of piperacillin-tazobactam therapy. Since a susceptibility breakpoint has not been established for B. wadsworthia, standardized treatment guidelines are currently unavailable. This case represents the first successful treatment of B. wadsworthia bacteremia with piperacillin-tazobactam, suggesting it may be an effective therapeutic option for infections caused by B. wadsworthia.