Objective To investigate the clinical features of the two most common types of pyogenic liver abscess in clinical practice,Klebsiella pneumoniae liver abscess( KPLA) and Escherichia coli liver abscess( ECLA),and to provide a reference for early diagnosis and effective treatment. Methods A retrospective analysis was performed for the clinical data of 371 patients with liver abscess who were admitted to The Second Affiliated Hospital of Air Force Medical University from March 2005 to July 2018,among whom 145 patients tested positive for pathogen. KPLA patients and ECLA patients were compared in terms of clinical features,laboratory examination,radiological examination,and prognosis. The t-test or the Mann-Whitney U test was used for comparison of continuous data between two groups,and the chi-square test or the Fisher's exact test was used for comparison of categorical data between two groups. A multivariate logistic regression analysis was used to determine the influencing factors for prognosis. Results Among the 145 patients that tested positive for pathogen,66 tested positive for Klebsiella pneumonia and 42 tested positive for Escherichia coli. Compared with the KPLA patients,the ECLA patients tended to have an older age( t =-2. 25,P = 0. 027),biliary diseases( χ2= 10. 019,P = 0. 002),a history of abdominal surgery( χ2= 27. 481,P < 0. 001),tumor( χ2= 17. 745,P < 0. 001),and a significantly higher proportion of individuals with recurrent liver abscess( χ2=13. 745,P < 0. 001). KPLA was often observed in patients with diabetes( χ2= 17. 505,P < 0. 001). As for laboratory examination,compared with the KPLA patients,the ECLA patients had a significant increase in total bilirubin( U = 880. 000,P = 0. 001) and significant reductions in albumin( t =-2. 625,P = 0. 010) and platelet count( U = 1719. 000,P = 0. 036). Radiological examination showed that there was a higher proportion of patients with multiple liver abscess in ECLA( χ2= 23. 372,P < 0. 001),while KPLA often had an abscess diameter of > 5 cm( χ2= 7. 637,P = 0. 006). As for complications,the ECLA patients were more likely to develop pulmonary infection( χ2=18. 857,P < 0. 001) and emphysema( P = 0. 013). ECLA patients were more likely to have multidrug-resistant organisms,and most patients were treated with antibiotics combined with ultrasound-guided percutaneous drainage in both groups. The multivariate logistic regression analysis showed that Acute Physiology and Chronic Health Evaluation Ⅱ score on admission( odds ratio = 0. 049,95% confidence interval: 0. 026-0. 266,P < 0. 001) was an influencing factor for prognosis. Conclusion ECLA is commonly seen in elderly patients with biliary diseases,with easy recurrence,multiple abscesses on radiological examination,and a high proportion of pulmonary infection and emphysema. There is a high positive rate of extended-spectrum beta-lactamases produced by ECLA,and therefore,antibiotics should be used reasonably in the early stage.