Grup de Microbiologia Clínica i Malalties Infeccioses, Departament de Biologia, Facultat de Ciències, Universitat de Girona, Girona, Spain.
Appl Environ Microbiol. 2012 Jan;78(2):420-8. doi: 10.1128/AEM.06858-11. Epub 2011 Nov 18.
Faecalibacterium prausnitzii is one of the most abundant commensal bacteria in the healthy human large intestine, but information on genetic diversity and substrate utilization is limited. Here, we examine the phylogeny, phenotypic characteristics, and influence of gut environmental factors on growth of F. prausnitzii strains isolated from healthy subjects. Phylogenetic analysis based on the 16S rRNA sequences indicated that the cultured strains were representative of F. prausnitzii sequences detected by direct analysis of fecal DNA and separated the available isolates into two phylogroups. Most F. prausnitzii strains tested grew well under anaerobic conditions on apple pectin. Furthermore, F. prausnitzii strains competed successfully in coculture with two other abundant pectin-utilizing species, Bacteroides thetaiotaomicron and Eubacterium eligens, with apple pectin as substrate, suggesting that this species makes a contribution to pectin fermentation in the colon. Many F. prausnitzii isolates were able to utilize uronic acids for growth, an ability previously thought to be confined to Bacteroides spp. among human colonic anaerobes. Most strains grew on N-acetylglucosamine, demonstrating an ability to utilize host-derived substrates. All strains tested were bile sensitive, showing at least 80% growth inhibition in the presence of 0.5 μg/ml bile salts, while inhibition at mildly acidic pH was strain dependent. These attributes help to explain the abundance of F. prausnitzii in the colonic community but also suggest factors in the gut environment that may limit its distribution.
普拉梭菌（Faecalibacterium prausnitzii）是健康人体大肠中最丰富的共生细菌之一，但有关其遗传多样性和底物利用的信息有限。在这里，我们研究了从健康受试者中分离出的普拉梭菌菌株的系统发育、表型特征以及肠道环境因素对其生长的影响。基于 16S rRNA 序列的系统发育分析表明，培养的菌株代表了直接分析粪便 DNA 检测到的普拉梭菌序列，并将可用的分离株分为两个谱系。大多数测试的普拉梭菌菌株在厌氧条件下于苹果果胶上生长良好。此外，普拉梭菌菌株在与另两种丰富的果胶利用物种（拟杆菌属和真杆菌属）的共培养物中成功竞争，以果胶为底物，这表明该物种对结肠中果胶的发酵有贡献。许多普拉梭菌分离株能够利用糖醛酸进行生长，这种能力以前被认为仅限于人类结肠厌氧菌中的拟杆菌属。大多数菌株在 N-乙酰葡萄糖胺上生长，表明其具有利用宿主来源底物的能力。所有测试的菌株均对胆盐敏感，在存在 0.5μg/ml 胆盐的情况下表现出至少 80%的生长抑制，而在酸性 pH 下的抑制则取决于菌株。这些特性有助于解释普拉梭菌在结肠群落中的丰富度，但也表明肠道环境中可能限制其分布的因素。
