Mutagenic Analysis of the Clostridium difficile Flagellar Proteins, FliC and FliD, and Their Contribution to Virulence in Hamsters
Mutagenic Analysis of the Clostridium difficile Flagellar Proteins, FliC and FliD, and Their Contribution to Virulence in Hamsters
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DOI：
10.1128/iai.05305-11
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发表时间：
2011-10-01
影响因子：
3.1
通讯作者：
Armstrong, Glen D.
中科院分区：
文献类型：
--
作者：
Dingle, Tanis C.;Mulvey, George L.;Armstrong, Glen D.
虽然已知毒素A和B是艰难梭菌感染急性期的重要贡献者，但在这些生物体的整体发病机制中，定植和粘附宿主组织的作用仍不清楚。因此，我们使用最近引入的基于内含子的ClosTron基因中断系统来消除两种报道的艰难梭菌定植因子，主要鞭毛结构亚基（FliC）和鞭毛帽蛋白（FliD）的表达，以更深入地了解鞭毛和运动如何促进艰难梭菌的致病策略。结果表明，中断fliC或fliD基因会导致艰难梭菌鞭毛的完全丧失，以及运动性。然而，fliC和fliD突变菌株都比野生型630 Delta erm菌株更好地粘附在人肠道来源的Caco-2细胞上，这表明鞭毛和运动并不有助于甚至可能干扰艰难梭菌在体外对上皮细胞表面的粘附。此外，我们发现突变菌株对仓鼠的毒力更强，这表明鞭毛对毒力来说是不必要的，或者抑制运动可能是艰难梭菌在仓鼠中采用的一种致病策略。
Although toxins A and B are known to be important contributors to the acute phase of Clostridium difficile infection, the role of colonization and adherence to host tissues in the overall pathogenesis of these organisms remains unclear. Consequently, we used the recently introduced intron-based ClosTron gene interruption system to eliminate the expression of two reported C. difficile colonization factors, the major flagellar structural subunit (FliC) and the flagellar cap protein (FliD), to gain greater insight into how flagella and motility contribute to C. difficile's pathogenic strategy. The results demonstrate that interrupting either the fliC or the fliD gene results in a complete loss of flagella, as well as motility, in C. difficile. However, both the fliC and fliD mutant strains adhered better than the wild-type 630 Delta erm strain to human intestine-derived Caco-2 cells, suggesting that flagella and motility do not contribute to, or may even interfere with, C. difficile adherence to epithelial cell surfaces in vitro. Moreover, we found that the mutant strains were more virulent in hamsters, indicating either that flagella are unnecessary for virulence or that repression of motility may be a pathogenic strategy employed by C. difficile in hamsters.