Pylephlebitis Caused by Bacillus subtilis and Fusobacterium nucleatum.

A 90-year-old man presented with a 3-day history of general malaise. He was febrile (39.3°C) but the initial evaluation did not reveal the cause of the fever. After admission, Bacillus subtilis and Fusobacterium nucleatum were grown from multiple sets of blood cultures. In addition, contrast-enhanced computed tomography revealed thrombi in the portal vein and superior mesenteric vein; he was diagnosed with pylephlebitis. After receiving antimicrobial treatment and anticoagulation, the patient was cured. Pylephlebitis is a rare condition and may be the cause of unknown fevers. This is the first reported case of pylephlebitis caused by Bacillus subtilis.