Objective Following ileal resection for Crohn’s disease (CD), recurrence is very frequent. Although several clinical risk factors of recurrence have been identified, predicting relapse remains challenging. Performing an ileocolonoscopy within the first year after surgery is currently recommended to assess endoscopic recurrence and to adjust the treatment. We took advantage of a large prospective multicentric cohort to investigate the role of the ileal mucosa-associated microbiota in postoperative endoscopic recurrence. Patients and methods Ileal mucosa-associated microbiota was analysed by 16S sequencing at the time of surgery and/or of endoscopic evaluation in 201 patients (288 samples in total) prospectively recruited in France. Results Ileal mucosa-associated microbiota exhibits profound changes following surgery in CD. Compared with non-recurrence setting, endoscopic recurrence is associated with strong changes in ileal mucosa-associated microbiota that are highly reminiscent of those observed generally in ileal CD compared with healthy subjects with a reduction in alpha diversity, an increase in several members of the Proteobacteria phylum and a decrease in several members of the Lachnospiraceae and the Ruminococcaceae families within the Firmicutes phylum. At the time of surgery, we identified several bacterial taxa associated with endoscopic recurrence and that can better predict relapse than usual clinical risk factors. Conclusion Surgery has an important impact on ileal mucosa-associated microbiota. Postoperative endoscopic recurrence is associated with changes in microbiota composition and alpha diversity. The gut microbiota has the potential to predict postoperative evolution and recurrence.

中文翻译：

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回肠黏膜相关微生物群预测克罗恩病术后内镜复发的重要性

目的 克罗恩病 (CD) 回肠切除术后，复发非常频繁。尽管已经确定了几种复发的临床危险因素，但预测复发仍然具有挑战性。目前建议在手术后第一年内进行回肠结肠镜检查，以评估内窥镜复发情况并调整治疗方案。我们利用一个大型前瞻性多中心队列研究回肠黏膜相关微生物群在术后内镜复发中的作用。患者和方法 在法国前瞻性招募的 201 名患者（共 288 个样本）中，在手术和/或内窥镜评估时通过 16S 测序分析了回肠黏膜相关微生物群。结果 回肠黏膜相关微生物群在 CD 手术后表现出深刻的变化。与非复发情况相比，内镜下复发与回肠黏膜相关微生物群的强烈变化有关，与健康受试者相比，回肠黏膜相关微生物群的强烈变化让人联想到通常在回肠 CD 中观察到的那些，α 多样性降低，变形杆菌的几个成员增加门和厚壁菌门内毛螺菌科和瘤胃球菌科的几个成员减少。在手术时，我们确定了几种与内窥镜复发相关的细菌分类群，它们比通常的临床危险因素可以更好地预测复发。结论 手术对回肠黏膜相关微生物群有重要影响。术后内窥镜复发与微生物群组成和α多样性的变化有关。