Bifidobacterial species are common inhabitants of the gut of human infants during the period when milk is a major component of the diet. Bifidobacterium breve, Bifidobacterium bifidum, Bifidobacterium longum subspecies longum, and B. longum subspecies infantis have been detected frequently in infant feces, but subsp. infantis may be disadvantaged numerically in the gut of infants in westernized countries. This may be due to the different durations of breast milk feeding in different countries. Supplementation of the infant diet or replacement of breast milk using formula feeds is common in western countries. Formula milks often contain galacto- and/or fructo-oligosaccharides (‘GOS’, ‘FOS’, respectively) as additives to augment the concentration of oligosaccharides in ruminant milks, but the ability of subsp. infantis to utilize these potential growth substrates when in competition with other bifidobacterial species is unknown. We compared the growth and oligosaccharide utilization of GOS and FOS by bifidobacterial species in pure and co-culture. Short chain GOS and FOS (degree of polymerization [DP] 2 and 3) were favored growth substrates for strains of B. bifidum and B. longum subsp. longum, whereas both B. breve and B. longum subsp. infantis had ability to utilize both short and longer chain GOS and FOS (DP 2-6). B. breve was nevertheless numerically dominant over subsp. infantis in co-cultures. This was probably related to the slower use of GOS of DP3 by subsp. infantis, indicating that the kinetics of substrate utilization is an important ecological factor in the assemblage of gut communities.

Importance The kinds of bacteria that form the collection of microbes (the microbiota) in the gut of human infants may influence health and well-being. Knowledge of how the composition of the infant diet influences the assemblage of the bacterial collection is therefore important because dietary interventions may offer opportunities to alter the microbiota with the aim of improving health. Bifidobacterium longum subspecies infantis is a well-known bacterial species, but under modern child-rearing conditions it may be disadvantaged in the gut. Modern formula milks often contain particular oligosaccharide additives that are generally considered to support bifidobacterial growth. However, studies of the ability of various bifidobacterial species to grow together while using these oligosaccharides have not been conducted. These kinds of studies are essential for developing concepts of microbial ecology related to the influence of human nutrition on the development of the gut microbiota.

在牛奶是饮食的主要成分期间，双歧杆菌是人类婴儿肠道的常见居民。短双歧杆菌，两歧双歧杆菌，长双歧杆菌亚种杆菌和长双歧杆菌亚种婴儿一直在婴幼儿粪便中经常发现，但亚种。婴儿在西方国家的婴儿肠道中可能在数量上处于不利地位。这可能是由于不同国家的母乳喂养时间不同。在西方国家，婴儿配方奶粉补充婴儿饮食或替代母乳很普遍。配方奶通常包含低聚半乳糖和/或低聚果糖（分别为“ GOS”，“ FOS”）作为添加剂，以提高反刍动物奶中低聚糖的浓度，但具有亚种的能力。婴儿与其他双歧杆菌物种竞争时，如何利用这些潜在的生长底物尚不明确。我们比较了纯和共培养中双歧杆菌物种对GOS和FOS的生长和寡糖利用。短链GOS和FOS（聚合度[DP] 2和3）是双歧双歧杆菌和长双歧杆菌亚种菌株的首选生长底物。longum，而B. breve和B. longum子亚种。婴儿具有利用短链和长链GOS和FOS的能力（DP 2-6）。然而，B。breve在数量上仍优于亚种。婴儿在共同文化中。这可能与subsp较慢地使用DP3的GOS有关。婴儿，表明底物利用的动力学是肠道群落集合的重要生态因素。

重要性形成人类婴儿肠道中微生物（微生物群）集合的细菌种类可能会影响健康和福祉。因此，了解婴儿饮食组成如何影响细菌集合的组成很重要，因为饮食干预可能会提供改变微生物群的机会，以改善健康。长双歧杆菌婴儿亚种是一种众所周知的细菌，但在现代育儿条件下，它可能对肠道不利。现代配方奶通常包含特定的低聚糖添加剂，通常认为它们可支持双歧杆菌的生长。然而，尚未进行各种双歧杆菌种类在使用这些寡糖时一起生长的能力的研究。这些研究对于开发与人类营养对肠道菌群发育的影响有关的微生物生态学概念至关重要。