Methanobrevibacter attenuation via probiotic intervention reduces flatulence in adult human: A non-randomised paired-design clinical trial of efficacy

Trial designThe aim of this study was to investigate which of the gut microbes respond to probiotic intervention, as well as study whether they are associated with gastrointestinal symptoms in a healthy adult human. For the experimental purpose, twenty-one healthy adults were recruited and received probiotic mixture, which is composed of five Lactobacilli strains and two Bifidobacteria strains, once a day for 60 days. Defecation survey and Bioelectrical Impedance Analysis were conducted pre- and post-administration to measure phenotypic differences. Stool samples of the subjects were collected twice.MethodsThe statistical analysis was performed for pair designed metagenome data with 11 phenotypic records of the bioelectrical impedance body composition analyzer and 6 responses of the questionnaires about gastrointestinal symptom. Furthemore, correlation-based network analysis was conducted for exploring complex relationships among microbiome communities.ResultsThe abundances of Citrobacter, Klebsiella, and Methanobrevibacter were significantly reduced, which are strong candidates to be highly affected by the probiotic administration. In addition, interaction effects were observed between flatulence symptom attenuation and decreasing patterns of the Methanobrevibacter abundance.ConclusionsThese results reveal that probiotic intervention modulated the composition of gut microbiota and reduced the abundance of potential pathogens (i.e. Citrobacter and Klebsiella). In addition, methanogens (i.e. Methanobrevibacter) associated with the gastrointestinal symptom in an adult human.

试验设计：本研究旨在探究哪些肠道微生物可响应益生菌干预，并探究这些微生物与健康成年人胃肠道症状的相关性。为达成实验目标，本研究招募了21名健康成年人，令其每日服用一次由5株乳杆菌（Lactobacilli）和2株双歧杆菌（Bifidobacteria）组成的益生菌复合制剂，干预周期共计60天。分别于干预前与干预后开展排便情况调查问卷与生物电阻抗分析（Bioelectrical Impedance Analysis），以测定表型差异。受试者共提供2次粪便样本。
方法：本研究针对配对设计的宏基因组数据、生物电阻抗体成分分析仪记录的11项表型数据，以及6项胃肠道症状调查问卷的应答结果开展统计分析。此外，本研究还实施了基于相关性的网络分析，以探究微生物组群落间的复杂相互作用关系。
结果：柠檬酸杆菌属（Citrobacter）、克雷伯菌属（Klebsiella）与甲烷短杆菌属（Methanobrevibacter）的丰度显著降低，上述三类微生物均为受益生菌干预影响显著的潜在候选对象。此外，本研究还观察到胀气症状缓解与甲烷短杆菌属丰度下降模式之间存在交互效应。
结论：本研究结果显示，益生菌干预可调节肠道菌群组成，并降低潜在致病菌（即柠檬酸杆菌属与克雷伯菌属）的丰度。此外，本研究还证实，产甲烷古菌（即甲烷短杆菌属）与成年人的胃肠道症状存在相关性。