Anal fistula is a common proctological disease, but the thorough mechanisms of the anal fistula formation are still unclear. An increasing number of studies have revealed the crucial role of gut microbiota in intestinal diseases. We used 16S rRNA gene sequencing to analyze the intestinal microbiome in order to determine whether there are differences in the microbiome between anal fistula patients and healthy individuals. The microbiome samples were extracted by repeatedly wiping the rectal wall with intestinal swab. Before this operation, the whole intestine of all participants was irrigated and the score of the Boston bowel preparation scale reached 9. The biodiversity of gut microbiome of rectum revealed significant difference between anal fistula patients and healthy individuals. 36 discriminative taxa were identified by LEfSe analysis between two groups. At the phylum level, Synergistetes was enriched in anal fistula patients, while Proteobacteria was higher in healthy individuals. We also found that at the genus level, Blautia, Faecalibacterium, Ruminococcus, Coprococcus, Bacteroides, Clostridium, Megamonas and Anaerotruncus were highly enriched in anal fistula patients, while the microbiome of healthy individuals was enriched with Peptoniphilus and Corynebacterium. Spearman correlations showed the extensive and close association among genera and species. Finally, a diagnostic prediction model was constructed by random forest classifier, and the area under curve (AUC) reached 0.990. This study gave an important hint for analyzing gut microbiome of rectum in anal fistula patient.

Keypoints.

We use the 16S rRNA gene sequencing to test the microbiome samples extracted from the intestinal swab. This is the first study to explore the gut microbiome of rectum using this workflow. We also found the distinct gut microbiome of rectum differences between anal fistula patients and healthy individuals.

肛瘘是一种常见的直肠疾病，但肛瘘形成的具体机制尚不清楚。越来越多的研究揭示了肠道菌群在肠道疾病中的关键作用。我们使用 16S rRNA 基因测序分析肠道微生物组，以确定肛瘘患者和健康个体之间的微生物组是否存在差异。通过用肠拭子反复擦拭直肠壁来提取微生物组样本。在本次手术前，所有参与者的全肠都经过冲洗，波士顿肠道准备量表得分达到9分。直肠肠道微生物群的生物多样性显示肛瘘患者与健康个体之间存在显着差异。两组之间的 LEfSe 分析确定了 36 个有区别的分类群。在门级，Synergistetes在肛瘘患者中富集，而Proteobacteria在健康个体中较高。我们还发现，在属水平上，Blautia、Faecalibacterium、Ruminococcus、Coprococcus、Bacteroides、Clostridium、Megamonas和Anaerotruncus在肛瘘患者中高度富集，而健康个体的微生物组则富含Peptoniphilus和Corynebacterium. 斯皮尔曼相关性显示了属和种之间广泛而密切的关联。最后通过随机森林分类器构建诊断预测模型，曲线下面积（AUC）达到0.990。该研究为分析肛瘘患者直肠肠道菌群提供了重要提示。

关键点。

我们使用 16S rRNA 基因测序来测试从肠道拭子中提取的微生物组样本。这是第一项使用此工作流程探索直肠肠道微生物组的研究。我们还发现肛瘘患者和健康个体之间直肠的不同肠道微生物组存在差异。