艰难梭菌对人可引起致死性假膜性肠炎,常发生于抗生素治疗之后。此菌可产生toxA、toxB两种毒素。toxA是一种肠毒素,可引起肠粘膜损伤;toxB单独对肠粘膜作用不大,仅在组织受toxA损伤后才起致死作用。此两毒素的分子机制仍不明确,主要在于无法使艰难梭菌转化。但有人认为在艰难梭菌toxB基因上游有一段与大肠杆菌Shine-Dalgarno(SD)序列相似的片段,此段可能有启动子活性。本文据此进行了研究。 Clostridium difficile can cause fatal pseudomembranous colitis, often after antibiotic treatment. The bacteria can produce toxA, toxB two toxins. toxA is an enterotoxin, can cause intestinal mucosal injury; toxB alone has little effect on the intestinal mucosa, only in tissue damage by toxA after the lethal effect. The molecular mechanism of these two toxins remains unclear, mainly due to inability to convert C. difficile. However, it is thought that there is a fragment upstream of the C. difficile toxB gene that is similar to the E. coli Shine-Dalgarno (SD) sequence, which may have promoter activity. This article has carried on the research according to this.