Clarke R C, Gyles C L
Am J Vet Res. 1987 Mar;48(3):504-10.
A ligated intestine model in calves, pigs, and rabbits was tested for its value as an indicator of virulence of potential vaccine strains of Salmonella typhimurium. A wild virulent strain (3860C), a laboratory strain LT2, and mutants of these 2 strains were evaluated. Inoculation of calf intestinal segments with strain 3860C revealed that fluid responses were greatest in the proximal portion of the small intestine and that doses greater than 10(7) organisms were required to produce fluid responses and mucosal damage. Immunoperoxidase-stained sections of intestine revealed that a large dose of Salmonella organisms was required before mucosal invasion could be detected. Aromatic (aroA), galactose epimerase (galE), and diaminopimelic acid (dap) mutants of strain 3860C all resulted in much less fluid response, mucosal invasion, and mucosal damage compared with those by the parent organism. Strain LT2 induced such weak responses that it was not possible to evaluate reductions in virulence of its mutants. In 6-week-old pigs, there was no fluid response to any strains; however, in 1-week-old pigs, there was fluid response to the wild strain and some of its mutants. In adult rabbits, fluid responses were not observed, except when the wild strain was inoculated in the proximal portion of the small intestine. The calf and 1-week-old pig models appeared to be best suited for assessment of virulence of mutant strains of S typhimurium.
对犊牛、猪和兔的结扎肠模型进行了测试，以评估其作为鼠伤寒沙门氏菌潜在疫苗株毒力指标的价值。评估了一株野生强毒株（3860C）、一株实验室菌株LT2以及这两株菌株的突变体。用3860C菌株接种犊牛肠段发现，小肠近端的液体反应最大，且需要大于10(7)个菌量才能产生液体反应和黏膜损伤。肠组织免疫过氧化物酶染色切片显示，在检测到黏膜侵袭之前需要大量的沙门氏菌。与亲本菌株相比，3860C菌株的芳香族（aroA）、半乳糖表异构酶（galE）和二氨基庚二酸（dap）突变体均导致液体反应、黏膜侵袭和黏膜损伤明显减少。LT2菌株引起的反应很弱，以至于无法评估其突变体毒力的降低情况。在6周龄的猪中，对任何菌株均无液体反应；然而，在1周龄的猪中，对野生菌株及其一些突变体有液体反应。在成年兔中，未观察到液体反应，除非在小肠近端接种野生菌株。犊牛和1周龄猪模型似乎最适合评估鼠伤寒沙门氏菌突变株的毒力。
