肠源性感染——无菌和SPF动物的实验研究

The Bacterial Translocation of Indigenous Flora from Gastrointestinal Tract

肠道内细菌通过肠粘膜屏障侵入到肠道以外部位形成感染的过程称之为“细菌移居”或肠源性感染。本实验利用无菌和无特殊致病菌动物进行研究,证实肠道中的常驻菌乳酸杆菌和非常驻菌肠炎沙门氏菌,均能够通过破坏肠粘膜的机械性屏障侵入体内形成肠源性感染。肠道中细菌主要是通过细胞内途径穿过肠粘膜屏障。肠粘膜上皮细胞内的溶酶体是肠粘膜抗感染防御屏障中的重要成分。

Translocatidn rate (TR) of the newly described species of indigenous bacteria, lactobacillus murinus is compared with indigenous lactobacillus acidophilus and nonindigenous Salmonella enteritidis. Groups of germfree or antibiotic- decontaminated, specific-pathogen- free mice are monoassociated with each of these strains and tested at various intervals for translocation to the mesenteric lymph nodes. TR of each bacterium is expressed by the number of bacteria per gram mesenteric lymph node. TRs of the bacteria are in a decreasing order as S. enteritidis, L.murinus and L.acidophilus. Degrees of the histological damage of the gastrointestinal mucosa follow the same order pattern. L.murinus translocates from the gastrointestinal tract at a surprisingly high rate for an indigenous bacterial strain and the translocation is associated with mucosal damage. Passage of the viable bacteria from the gastrointestinal tract to the mesenteric node is mainly due to the destruction of the intestinal barrier.