PDF(Pubmed)
Abstract：
Enteroaggregative E. coli (EAEC) is a major cause of diarrhea worldwide. EAEC are highly adherent to cultured epithelial cells and make biofilms. Both adherence and biofilm formation rely on the presence of aggregative adherence fimbriae (AAF). We compared biofilm formation from two EAEC strains of each of the five AAF types. We found that AAF type did not correlate with the level of biofilm produced. Because the composition of the EAEC biofilm has not been fully described, we stained EAEC biofilms to determine if they contained protein, carbohydrate glycoproteins, and/or eDNA and found that EAEC biofilms contained all three extracellular components. Next, we assessed the changes to the growing or mature EAEC biofilm mediated by treatment with proteinase K, DNase, or a carbohydrate cleavage agent to target the different components of the matrix. Growing biofilms treated with proteinase K had decreased biofilm staining for more than half of the strains tested. In contrast, although sodium metaperiodate only altered the biofilm in a quantitative way for two strains, images of biofilms treated with sodium metaperiodate showed that the EAEC were more spread out. Overall, we found variability in the response of the EAEC strains to the treatments, with no one treatment producing a biofilm change for all strains. Finally, once formed, mature EAEC biofilms were more resistant to treatment than biofilms grown in the presence of those same treatments.
摘要：
肠聚集性大肠杆菌(EAEC)是世界范围内腹泻的主要原因。EAEC高度粘附于培养的上皮细胞并产生生物膜。粘附和生物膜形成都依赖于聚集粘附菌毛（AAF）的存在。我们比较了五种AAF类型中每一种的两种EAEC菌株的生物膜形成。我们发现AAF类型与产生的生物膜水平无关。由于EAEC生物膜的组成尚未完全描述，我们对EAEC生物膜进行染色以确定它们是否含有蛋白质，碳水化合物糖蛋白，和/或eDNA，发现EAEC生物膜包含所有三种细胞外成分。接下来,我们评估了蛋白酶K处理介导的生长或成熟的EAEC生物膜的变化，DNase,或碳水化合物裂解剂靶向基质的不同组分。对于超过一半的测试菌株，用蛋白酶K处理的生长生物膜降低了生物膜染色。相比之下,尽管偏高碘酸钠仅以定量方式改变了两个菌株的生物膜，用偏高碘酸钠处理的生物膜图像显示EAEC更分散。总的来说,我们发现EAEC菌株对治疗反应的变异性，没有一种治疗方法对所有菌株产生生物膜变化。最后,一旦形成，成熟的EAEC生物膜比在那些相同处理存在下生长的生物膜对处理更具抗性。
