Establishment of liver abscess model of Klebsiella pneumoniae in mice

To construct a stable and reliable animal model of Klebsiella pneumoniae liver abscess（KPLA）, healthy ICR mice weighing around 18 g were selected, and a highly virulent clinical isolate of Klebsiella pneumoniae, strain KP001, was used as the modeling strain. The inoculation methods（gavage, intranasal, and intraperitoneal injection）and doses were explored, and the serum samples from successfully modeled mice were tested for biochemical indicators such as alanine aminotransferase（ALT）, aspartate aminotransferase（AST）, alkaline phosphatase（ALP）, gamma-glutamyltransferase（GGT）, albumin, lactate dehydrogenase（LDH）, and total bilirubin. The results showed that mice gavaged had a survival rate of 100%, but no abscesses in the liver; mice intranasally inoculated had a mortality rate of 100%, with obvious lung lesions, and 40% of the dead mice developed liver abscesses; after intraperitoneal injection with 1×10⁶ CFU of bacteria, the survival rate of mice was 87.5%, and all surviving mice had abscesses in the liver, with a modeling success rate of 100%. Pathological sections showed that the liver cells of successfully modeled mice were disordered, with a large number of inflammatory cells infiltrating around the central vein. Biochemical indicator tests showed that compared with the control mice, the serum samples of successfully modeled mice had a significantly increased level of gamma-glutamyltransferase（p＜0.001）, a significantly decreased level of alkaline phosphatase（p＜0.01）, alanine aminotransferase（p＜0.05）and albumin（p＜0.05）. The results indicated that by intraperitoneal injection with 1×10⁶ CFU of KP001 strain, a KPLA mouse model could be successfully established; biochemical indicators such as gamma-glutamyltransferase and alkaline phosphatase can be used to evaluate the effectiveness of model establishment. This study is of great significance for the study of the pathogenesis of KPLA and the evaluation of therapeutic effects.