Summary

A 68-year-old Japanese man with alcoholic liver cirrhosis was admitted to our hospital because of fever and haematemesis. On day 3, his blood culture became positive for Gram-negative bacilli and Gram-positive cocci, and contrast-enhanced abdominal CT revealed acute septic thrombophlebitis of the superior mesenteric vein with caecal diverculitis. Antimicrobial therapy with ampicillin–sulbactam and anticoagulant therapy were started and the blood culture grew Bacteroides fragilis and Streptococcus intermedius. On hospital day 7, the patient's condition began to improve in response to the therapy, therefore, the ampicillin–sulbactam and anticoagulant therapy was continued for 42 days. The patient was discharged home on hospital day 45. B fragilis bacteraemia of unknown source should caution the physician to search for an intra-abdominal focus, such as thrombosis of the portal vein or mesenteric vein.