Establishment of the Mouse Model of Klebsiella pneumoniae Liver Abscess

In order to construct a stable and reliable animal model of Klebsiella pneumoniae liver abscess (KPLA), about 18 g healthy ICR mice were selected, and the highly virulent animal-derived Klebsiella pneumoniae clinical isolated strain KP001 was used as the model strain. Then, the inoculation methods (including the gastric irrigation, nasal drip and intraperitoneal injection, with the number of inoculated bacteria was 1×10⁷ CFU) and the inoculation dosage were explored. The biochemical indexes of serum samples from the mice with successful modeling were determined, including the alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, γ-glutamyl transferase, albumin, lactate dehydrogenase, and total bilirubin. The results showed that the survival rate of mice treated with gastric irrigation was 100%, but there was no abscess in the liver. The mortality rate of mice treated with nasal dripping was 100%, with obvious lung lesions, and the liver abscess occurred in 40% of the dead mice. After the intraperitoneal injection of 1×10⁶ CFU bacteria, the survival rate of mice was more than 75%, and the liver abscesses appeared in the surviving mice, with the modeling rate of 100%. The pathological sections showed that the liver cells of the successfully modeled mice arranged in disorder, and a large number of inflammatory cells infiltrated around the central vein. The detection of biochemical indicators showed that compared with the control mice, the γ-glutamyl transferase in the serum samples of the successfully modeled mice was significantly increased (P＜0.01), the alkaline phosphatase was significantly decreased (P＜0.01), and the alanine aminotransferase and albumin were significantly decreased (P＜0.05). In conclusion, the analysis showed that the KPLA mouse model could be successfully constructed by the intraperitoneal injection of 1×10⁶ CFU KP001 strain. The biochemical indexes such as γ-glutamyl transferase and alkaline phosphatase could be used to evaluate the effect of model establishment.