Pyogenic liver abscess associated with Klebsiella oxytoca: Mimicking invasive liver abscess syndrome

A pyogenic liver abscess (PLA) is a space-occupying lesion in the liver that is associated with significant morbidity and mortality. We herein present the case of a Japanese 76-year-old man who visited our hospital with fever and back pain lasting 3 weeks after endoscopic treatment for common bile duct stones. He was accompanied by poorly controlled diabetes mellitus (DM) with an HbA1c of 9.7 %. Laboratory tests disclosed elevated C-reactive protein level (22.1 mg/dL) and white cell count (11,910/μL). Abdominal computed tomography (CT) revealed hypodense lesions in the right liver lobe, with abdominal ultrasonography showing an echogenicity-mixed hypoechoic lesion. Percutaneous needle aspiration of a liver lesion was performed under suspicion of a PLA. Subsequent enhanced CT and magnetic resonance imaging confirmed the hepatic lesions in the right lobe as well as a septic pulmonary embolism, right hepatic vein thrombosis, spondylodiscitis, and a retroperitoneal abscess. Gram staining of the abscess drainage revealed gram-negative bacteria. The above findings indicated invasive liver abscess syndrome (ILAS) caused by Klebsiella pneumoniae. However, further examination of blood, urine, and abscess drainage cultures revealed positivity for Klebsiella oxytoca. This case illustrates that K. oxytoca may cause ILAS-like symptoms. Screening for systemic metastatic infection should be considered in patients with PLA due to K. oxytoca in whom therapeutic intervention has been delayed, especially in patients with poorly controlled DM.