Crohn’s disease (CD) is characterized by chronic inflammation of the human intestine. Several studies have demonstrated that the intestinal mucosa of CD patients in Western countries is abnormally colonized by adherent-invasive Escherichia coli (AIEC) strains. However, no studies to date have focused on the involvement of such E. coli strains in CD patients in Brazil. Here, we characterized E. coli strains associated with the ileal mucosa of Brazilian CD patients (ileal biopsies from 35 subjects, 24 CD patients and 11 controls). The colonization level of adherent Enterobacteriaceae associated with the ileal mucosa of CD patients was significantly higher than that of the controls. The proportions of E. coli strains belonging to phylogroups B1 and B2 were two-fold higher in strains isolated from CD patients than in those isolated from controls. CD patients in the active phase harbored 10-fold more E. coli belonging to group B2 than CD patients in remission. Only a few E. coli isolates had invasive properties and the ability to survive within macrophages, but 25% of CD patients in Brazil (6/24) harbored at least one E. coli strain belonging to the AIEC pathobiont. However, fimH sequence analysis showed only a few polymorphisms in the FimH adhesin of strains isolated in this study compared to the FimH adhesin of AIEC collections isolated from European patients. Mucosa-associated E. coli strains colonize the intestinal mucosa of Brazilian CD patients. However, the strains isolated from Brazilian CD patients have probably not yet co-evolved with their hosts and therefore have not fully developed a strong adherent-invasive phenotype. Thus, it will be crucial to follow in the future the emergence and evolution of AIEC pathobionts in the Brazilian population.

中文翻译：

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从巴西克罗恩病患者中分离出的与粘膜相关的大肠杆菌菌株的表征。

克罗恩氏病（CD）的特征是人类肠道的慢性炎症。多项研究表明，西方国家CD患者的肠粘膜被粘附侵袭性大肠杆菌（AIEC）菌株异常定殖。但是，迄今为止，没有研究集中在巴西的CD患者中涉及这种大肠杆菌菌株。在这里，我们表征了与巴西CD患者回肠粘膜相关的大肠杆菌菌株（来自35名受试者，24名CD患者和11名对照的回肠活检）。与CD患者回肠粘膜相关的粘附性肠杆菌科细菌的定植水平显着高于对照组。从CD患者分离的菌株中，属于系统群B1和B2的大肠杆菌菌株的比例是从对照分离的菌株中的两倍。处于活动期的CD患者所含的B2组大肠杆菌比缓解期的CD患者多10倍。只有少数的大肠杆菌分离株具有侵袭性，并且能够在巨噬细胞中存活，但是在巴西（6/24）的CD患者中，有25％携带至少一种属于AIEC病原菌的大肠杆菌。但是，fimH序列分析显示，与从欧洲患者中分离出的AIEC集合的FimH粘附素相比，本研究中分离出的菌株的FimH粘附素仅具有少数多态性。粘膜相关的大肠杆菌菌株定居在巴西CD患者的肠粘膜上。但是，从巴西CD患者中分离出的菌株可能尚未与其宿主共同进化，因此尚未完全形成强粘附粘附表型。从而，