Eaton K A, Krakowka S
Dept. of Veterinary Pathobiology, Ohio State University, Columbus 43210, USA.
Scand J Gastroenterol. 1995 May;30(5):434-7. doi: 10.3109/00365529509093303.
Urease-negative Helicobacter pylori generated by insertional mutagenesis fails to colonize gnotobiotic piglets, and this effect is largely independent of gastric pH. The purpose of this study was to determine whether urease-negative H. pylori colonized gastric explants ex vivo.
Gastric mucosal explants derived from neonatal germ-free piglets were inoculated with either wild-type H. pylori or one of two mutants derived by insertional mutagenesis.
All three bacterial strains colonized explants. The level of colonization increased over the duration of the experiment, reaching 10(8)-10(9) cfu/g gastric mucosa by 72 h after inoculation. Morphologic evidence of colonization was similar to that observed in gnotobiotic piglets.
Colonization of explants was not affected by lack of urease. These results contrast with previous findings showing that urease activity is essential for colonization of piglets by H. pylori. Thus, urease-dependent colonization is dependent on an intact gastric microenvironment.
通过插入诱变产生的脲酶阴性幽门螺杆菌无法在无菌仔猪中定殖，且这种影响在很大程度上与胃内pH值无关。本研究的目的是确定脲酶阴性幽门螺杆菌是否能在体外胃外植体中定殖。
将来自新生无菌仔猪的胃黏膜外植体接种野生型幽门螺杆菌或通过插入诱变获得的两种突变体之一。
所有三种菌株均能在体外植体中定殖。定殖水平在实验过程中升高，接种后72小时达到每克胃黏膜10⁸-10⁹cfu。定殖的形态学证据与在无菌仔猪中观察到的相似。
外植体的定殖不受脲酶缺乏的影响。这些结果与之前显示脲酶活性对幽门螺杆菌在仔猪中定殖至关重要的研究结果形成对比。因此，依赖脲酶的定殖取决于完整的胃微环境。
