背景:炎症性肠病(IBD)是一个主要的公共卫生问题,病因尚不清楚。肠道微生物群的组成和功能的变化与这些病理有关,包括耗竭严格的厌氧菌,如普氏双杆菌。在其他厌氧菌中观察到的消耗证据较少,其中双歧杆菌。这项研究通过文化方法表征了从活性和非活性IBD患者的人类肠道微生物群分离的双歧杆菌的分类学和功能多样性,并评估了这些双歧杆菌是否可用作肠道健康的益生菌。
结果:从IBD患者(52例克罗恩病和26例溃疡性结肠炎患者)的肠道菌群中分离出341株双歧杆菌,与高比例的双歧杆菌菌株(分离的双歧杆菌28%)。在溃疡性结肠炎中,鉴定出的主要物种是牙本质芽孢杆菌(占分离的双歧杆菌的39%),在活动性和非活动性溃疡性结肠炎中。在克罗恩病,青少年芽孢杆菌是从非活跃患者中分离出来的主要物种(40%),而在活跃的克罗恩病患者中发现了相似量的牙本质芽孢杆菌和青春期芽孢杆菌。牙菌根的相对丰度随着年龄的增长而增加,克罗恩病和溃疡性结肠炎以及活动性和非活动性IBD患者。与从活性溃疡性结肠炎中分离的菌株相比,从非活性溃疡性结肠炎中分离的双歧杆菌对大肠杆菌LF82和肠道沙门氏菌ATCC14028的抗菌能力更为常见。最后,长芽孢杆菌被保留为具有最高益生菌潜力的菌株,因为它们是呈现胞外多糖合成的主要菌株。抗菌活性,和抗炎能力。通过计算机模拟分析,抗菌活性和EPS合成进一步与抗菌和EPS基因簇的存在相关。
结论:在IBD患者的微生物群中鉴定出不同的双歧杆菌分类谱。最丰富的物种是牙本质芽孢杆菌,主要与溃疡性结肠炎患者和青少年芽孢杆菌的微生物群有关,在克罗恩病患者的肠道微生物群中。此外,牙菌根的相对丰度随着年龄的增长而显著增加。此外,这项研究证明,双歧杆菌具有益生菌潜力(抗致病活性,胞外多糖的产生和抗炎活性),尤其是B.longum菌株,可以从活动性和非活动性克罗恩病和溃疡性结肠炎患者的肠道菌群中分离。
BACKGROUND: Inflammatory Bowel Diseases (IBD) are a major public health issue with unclear aetiology. Changes in the composition and functionality of the intestinal microbiota are associated with these pathologies, including the depletion of strict anaerobes such as Feacalibacterium prausnitzii. Less evidence is observed for depletion in other anaerobes, among which bifidobacteria. This study characterized the taxonomic and functional diversity of bifidobacteria isolated from the human intestinal microbiota in active and non-active IBD patients by a culturomics approach and evaluated if these bifidobacteria might be used as probiotics for gut health.
RESULTS: A total of 341 bifidobacteria were isolated from the intestinal microbiota of IBD patients (52 Crohn\'s disease and 26 ulcerative colitis patients), with a high proportion of Bifidobacterium dentium strains (28% of isolated bifidobacteria). In ulcerative colitis, the major species identified was B. dentium (39% of isolated bifidobacteria), in active and non-active ulcerative colitis. In Crohn\'s disease, B. adolescentis was the major species isolated from non-active patients (40%), while similar amounts of B. dentium and B. adolescentis were found in active Crohn\'s disease patients. The relative abundance of B. dentium was increased with age, both in Crohn\'s disease and ulcerative colitis and active and non-active IBD patients. Antibacterial capacities of bifidobacteria isolated from non-active ulcerative colitis against Escherichia coli LF82 and Salmonella enterica ATCC 14028 were observed more often compared to strains isolated from active ulcerative colitis. Finally, B. longum were retained as strains with the highest probiotic potential as they were the major strains presenting exopolysaccharide synthesis, antibacterial activity, and anti-inflammatory capacities. Antimicrobial activity and EPS synthesis were further correlated to the presence of antimicrobial and EPS gene clusters by in silico analysis.
CONCLUSIONS: Different bifidobacterial taxonomic profiles were identified in the microbiota of IBD patients. The most abundant species were B. dentium, mainly associated to the microbiota of ulcerative colitis patients and B. adolescentis, in the intestinal microbiota of Crohn\'s disease patients. Additionally, the relative abundance of B. dentium significantly increased with age. Furthermore, this study evidenced that bifidobacteria with probiotic potential (antipathogenic activity, exopolysaccharide production and anti-inflammatory activity), especially B. longum strains, can be isolated from the intestinal microbiota of both active and non-active Crohn\'s disease and ulcerative colitis patients.