Salmonella Indiana has emerged in recent years as an important zoonotic pathogen, but its pathogenicity has not been fully elucidated. In this study, using in vivo and in vitro animal and cellular experimental model systems, we evaluated the pathogenicity of Salmonella Indiana (S. Indiana) compared with three other serotypes of Salmonella, S. Enteritidis, S. Typhimurium and S. Thompson. The animal experiments included observations of clinical symptoms, pathological changes and determination of median lethal dose in mice. The adhesion and invasiveness and intracellular proliferative capacity of Salmonella in vitro were measured with the murine macrophage-like cell line RAW264.7 cells and the human colon adenocarcinoma cell line Caco-2 cells. The results of animal experiments showed that S. Indiana, S. Enteritidis, S. Typhimurium and S. Thompson caused histopathological changes in most organs to varying degrees, primarily in the liver and intestine of mice. The gross lesions included white necrotic foci on the liver surface with different levels. The histopathological changes of monocyte/macrophage infiltration and coagulative necrosis were observed in the liver. Intestinal villi became short and were sloughed off, and lymphocyte infiltration was found in the submucosa. Compared with the other serotypes, the pathological changes caused by S. Indiana were slighter and had a relatively high median lethal dose in mice. The results of adhesion and invasion tests showed that the intracellular growth trend of most Salmonella strains was positively correlated with the number of pathogens adhering to and invading cells. Compared with the strains of the other three serotypes, most S. Indiana strains exhibited significantly lower adhesion and invasiveness to RAW264.7 and Caco-2 cells within 30 min. Most S. Indiana strains displayed twice to four times lower intracellular proliferation within 24 h in RAW264.7 cells. In conclusion, S. Indiana was pathogenic, but its pathogenicity was lower than that of S. Typhimurium and S. Enteritidis, and was similar to that of S. Thompson.

印第安纳沙门氏菌近年来已成为一种重要的人畜共患病原体，但其致病性尚未得到充分阐明。在这项研究中，使用体内和体外动物和细胞的实验模型系统中，我们评估的致病性沙门氏菌印第安纳（小号与三个其他血清型进行比较。印第安纳州）的沙门氏菌，S.肠炎，S.鼠伤寒沙门氏菌和小号。汤普森 动物实验包括观察临床症状，病理变化以及确定小鼠的中值致死剂量。鼻咽癌的黏附侵袭和细胞内增殖能力。用鼠巨噬细胞样细胞系RAW264.7细胞和人结肠腺癌细胞系Caco-2细胞对沙门氏菌进行体外测量。动物实验结果表明，S。印第安纳州，S.肠炎，S.鼠伤寒沙门氏菌和S.汤普森（Thompson）在大多数器官中引起了不同程度的组织病理变化，主要是在小鼠的肝脏和肠道中。肉眼可见的病灶包括肝脏表面的白色坏死灶，水平不同。在肝脏中观察到单核细胞/巨噬细胞浸润和凝血坏死的组织病理学变化。肠绒毛变短并脱落，在粘膜下层发现淋巴细胞浸润。与其他血清型相比，印第安纳沙门氏菌引起的病理变化较轻，小鼠的致死剂量中位数相对较高。黏附和侵袭试验结果表明，大多数沙门氏菌的细胞内生长趋势。菌株与粘附和侵袭细胞的病原体数量呈正相关。与其他三个血清型，大多数菌株相比小号。印第安纳州菌株在30分钟内对RAW264.7和Caco-2细胞的粘附和侵袭力明显降低。大多数小号。在RAW264.7细胞中，印第安纳州菌株在24小时内的细胞内增殖降低了2到4倍。总之，S.印第安纳是致病的，但它的致病性比的降低S.鼠伤寒沙门氏菌和S.肠炎，并且是类似的S.汤普森。