Prognosis of liver abscess with no identified organism

Background: There are limited studies focusing on liver abscess with negative microbiological cultures. This study evaluated the clinical and prognostic differences of patients with culture-negative liver abscess (CNLA) compared to those with a positive culture (CPLA) and compared these factors between K. pneumoniae liver abscess (KLA) and E. coli liver abscess (ELA). Methods: A retrospective study of the patients who admitted with a liver abscess at two tertiary hospitals in Korea from 2012 to 2016 was performed. Results: Among a total of 402 patients with liver abscess, 61.2% had positive cultures. K. pneumoniae (n = 133) was the most common cause, followed by E. coli (n = 74). Patients with CPLA were significantly older (p = 0.02) and more frequently had cholelithiasis or biliary tract disease (p = 0.001) compared to patients with CNLA. In-hospital mortality (p = 0.63) and recurrence (p = 0.77) were no different between the two groups. The length of hospital stay was significantly longer in patients with CPLA (p = 0.03) compared with those with CNLA. Subgroup analysis for patients who received 3rd generation cephalosporins empirically showed that in-hospital mortality (p = 0.18) and recurrence (p = 0.27) were not also significantly different. Cholelithiasis, or biliary tract disease (p = 0.001), liver disease (p = 0.001), malignancy (p = 0.0001), and ESBL production (p = 0.0001) were found more frequently in patients with ELA compared with those with KLA. Conclusions: The prognosis of the CNLA patients was similar to that of the CPLA patients, although the length of hospital stay was shorter in the CNLA patients. The epidemiologic and clinical characteristics of the ELA patients are somewhat different than those of the KLA patients.