BACKGROUND:Etiologic organism is not frequently isolated despite multiple blood and fluid cultures during management of pyogenic liver abscess(PLA).Such culture negative pyogenic liver abscess(CNPLA) is routinely managed by antibiotics targeted to Klebsiella pneumoniae. In this study, we evaluated the outcomes of such clinical practice. METHODS: All the patients with CNPLA and Klebsiella pneumoniae PLA(KPPLA) admitted from January 2003 to December 2011 were included in the study. A retrospective review of medical records was performed and demographic, clinical and outcome data were collected.RESULTS: A total of 528 patients were treated as CNPLA or KPPLA over the study period. CNPLA presented more commonly with abdominal pain(P=0.024). KPPLA was more common in older age(P=0.029) and was associated with thrombocytopenia(P=0.001), elevated creatinine(P=0.002), bilirubin(P=0.001), alanine aminotransferase(P=0.006) and C-reactive protein level(P=0.036). CNPLA patients tend to have anemia(P=0.015) and smaller abscess(P=0.008). There was no difference in hospital stay(15.7 vs 16.8 days) or mortality(14.0% vs 11.0%). No patients required surgical drainage after initiation of medical therapy.CONCLUSION: Despite demographic and clinical differences between CNPLA and KPPLA, overall outcomes are not different. BACKGROUND: Etiologic organism is not frequently isolated despite multiple blood and fluid cultures during management of pyogenic liver abscess (PLA) .Such culture, negative pyogenic liver abscess (CNPLA) is routinely managed by antibiotics targeted to Klebsiella pneumoniae. In this study, we evaluated the METHODS of All Clinical Patients. METHODS: All the patients with CNPLA and Klebsiella pneumoniae PLA (KPPLA) admitted from January 2003 to December 2011 were included in the study. A retrospective review of medical records was performed and demographic, clinical and outcome data were collected .RESULTS: A total of 528 patients were treated as CNPLA or KPPLA over the study period. The CNPLA presented more commonly with abdominal pain (P = 0.024). KPPLA was more common in older age (P = 0.029) and was associated with thrombocytopenia P = 0.001), elevated creatinine (P = 0.002), bilirubin (P = 0.001), alanine aminotransferase (P = 0.006) and C-reactive protein level There was no difference in hospital stay (15.7 vs 16.8 days) or mortality (14.0% vs 11.0%). No patients required surgical drainage after initiation of medical therapy. CONCLUSION: Despite demographic and clinical differences between CNPLA and KPPLA, overall outcomes are not different.