A healthy intestinal microbiota is considered to be important for priming of the infants' mucosal and systemic immunity. Breast-fed infants typically have an intestinal microbiota dominated by different Bifidobacterium species. It has been described that allergic infants have different levels of specific Bifidobacterium species than healthy infants. For the accurate quantification of Bifidobacterium adolescentis, Bifidobacterium angulatum, Bifidobacterium bifidum, Bifidobacterium breve, Bifidobacterium catenulatum, Bifidobacterium dentium, Bifidobacterium infantis, and Bifidobacterium longum in fecal samples, duplex 5 nuclease assays were developed. The assays, targeting rRNA gene intergenic spacer regions, were validated and compared with conventional PCR and fluorescent in situ hybridization methods. The 5 nuclease assays were subsequently used to determine the relative amounts of different Bifidobacterium species in fecal samples from infants receiving a standard formula or a standard formula supplemented with galacto-and fructo-oligosaccharides (OSF). A breast-fed group was studied in parallel as a reference. The results showed a significant increase in the total amount of fecal bifidobacteria (54.8% ؎ 9.8% to 73.4% ؎ 4.0%) in infants receiving the prebiotic formula (OSF), with a diversity of Bifidobacterium species similar to breast-fed infants. The intestinal microbiota of infants who received a standard formula seems to resemble a more adult-like distribution of bifidobacteria and contains relatively more B. catenulatum and B. adolescentis (2.71% ؎ 1.92% and 8.11% ؎ 4.12%, respectively, versus 0.15% ؎ 0.11% and 1.38% ؎ 0.98% for the OSF group). In conclusion, the specific prebiotic infant formula used induces a fecal microbiota that closely resembles the microbiota of breast-fed infants also at the level of the different Bifidobacterium species.Generally, the intestinal microbiota of breast-fed infants is primarily composed of lactic acid bacteria, like bifidobacteria and lactobacilli. The microbiota of formula-fed infants is, on the other hand, more diverse and in general contains more Bacteroides, Clostridium, and Enterobacteriaceae (3,13,18,23). The intestinal microbiota may be modified temporarily by nutritional changes in the diet or by the consumption of pro-or prebiotics (9,14). Prebiotics are defined as nondigestible food ingredients that selectively stimulate the growth and/or activity of one or more bacterial species in the colon and thereby beneficially affect the host (16). For infant formulas, a specific mixture of galacto-oligosaccharides (GOS) and fructo-oligosaccharides (FOS) has been described that can serve as a growth factor for bifidobacteria, similar to the human milk oligosaccharides in breast milk (4, 6, 47). The number of bifidobacteria in infants receiving a formula containing GOS/ FOS was shown to be elevated in comparison to that of infants receiving a standard formula, but it is unclear whether the prebiotics stimulate specific Bifidobacterium species (5, 33, 42). In healthy br...

Our results show that impairment of the gastrointestinal tracts in human immunodeficiency virus (HIV)-positive patients is present in the early phases of HIV disease. This impairment is associated with alterations in gut microbiota and intestinal inflammatory parameters. These findings support the hypothesis that alterations at the gastrointestinal-tract level are a key factor in HIV pathogenesis.

The developing intestinal microbiota of breast-fed infants is considered to play an important role in the priming of the infants' mucosal and systemic immunity. Generally, Bifidobacterium and Lactobacillus predominate the microbiota of breast-fed infants. In intervention trials it has been shown that lactobacilli can exert beneficial effects on, for example, diarrhea and atopy. However, the Lactobacillus species distribution in breast-fed or formula-fed infants has not yet been determined in great detail. For accurate enumeration of different lactobacilli, duplex 5 nuclease assays, targeted on rRNA intergenic spacer regions, were developed for Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus delbrueckii, Lactobacillus fermentum, Lactobacillus paracasei, Lactobacillus plantarum, Lactobacillus reuteri, and Lactobacillus rhamnosus. The designed and validated assays were used to determine the amounts of different Lactobacillus species in fecal samples of infants receiving a standard formula (SF) or a standard formula supplemented with galacto-and fructo-oligosaccharides in a 9:1 ratio (OSF). A breast-fed group (BF) was studied in parallel as a reference. During the 6-week intervention period a significant increase was shown in total percentage of fecal lactobacilli in the BF group (0.8% ؎ 0.3% versus 4.1% ؎ 1.5%) and the OSF group (0.8% ؎ 0.3% versus 4.4% ؎ 1.4%). The Lactobacillus species distribution in the OSF group was comparable to breast-fed infants, with relatively high levels of L. acidophilus, L. paracasei, and L. casei. The SF-fed infants, on the other hand, contained more L. delbrueckii and less L. paracasei compared to breast-fed infants and OSF-fed infants. An infant milk formula containing a specific mixture of prebiotics is able to induce a microbiota that closely resembles the microbiota of BF infants.The intestinal microbiota composition is regarded as an important factor for infant health and well-being (15, 32). A lower incidence of gastrointestinal and other infections has been found in breast-fed infants (43), which partly may be related to their microbiota composition. The intestinal microbiota of breast-fed infants is generally dominated by the genera Bifidobacterium and Lactobacillus (35), which are able to inhibit the growth of pathogens by lowering the pH, due to the production of lactic and acetic acid (1), or by competing for nutrients and epithelial adhesion sites (2). In contrast to breast-fed infants, formula-fed infants possess a more diverse microbiota which is mainly composed of Bacteroides, Bifidobacterium, Staphylococcus, Escherichia coli, and Clostridium spp. (19).Several concepts are being used to modify the intestinal microbiota, such as nutritional changes or the consumption of pro-and/or prebiotics (10). Prebiotics are defined as nondigestible food ingredients that selectively stimulate the growth and/or activity of one or more bacteria in the colon and thereby beneficially affect the host (14). For infant formulas, a specific prebiotic mixture of galacto-oligos...

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Background: Galactooligosaccharides (GOS) and long-chain fructooligosaccharides (lcFOS) proliferate bifidobacteria in infant gut microbiota. However, it is not known how GOS and FOS influence the microbiota of pregnant women and whether a potential prebiotic effect is transferred to the offspring. Objectives: We aimed to test how supplementation with GOS and lcFOS (GOS/lcFOS) in the last trimester of pregnancy affects maternal and neonatal gut microbiota. Variables of fetal immunity were assessed as a secondary outcome. Design: In a randomized, double-blind, placebo-controlled pilot study, 48 pregnant women were supplemented 3 times/d with 3 g GOS/lcFOS (at a ratio of 9:1) or maltodextrin (placebo) from week 25 of gestation until delivery. Percentages of bifidobacteria and lactobacilli within total bacterial counts were detected by fluorescent in situ hybridization and quantitative polymerase chain reaction in maternal and neonatal (days 5, 20, and Ȃ182) stool samples. Variables of fetal immunity were assessed in cord blood by using flow cytometry and cytokine multiplex-array analysis. Results: The proportions of bifidobacteria in the maternal gut were significantly higher in the supplemented group than in the placebo group (21.0% and 12.4%, respectively; P ҃ 0.026); the proportion of lactobacilli did not differ between the groups. In neonates, bifidobacteria and lactobacilli percentages, diversity and similarity indexes, and fetal immune parameters did not differ significantly between the 2 groups. Mother-neonate similarity indexes of bifidobacteria decreased over time. Conclusions: GOS/lcFOS supplementation has a bifidogenic effect on maternal gut microbiota that is not transferred to neonates. The increased maternal bifidobacteria did not affect fetal immunity as measured by a comprehensive examination of cord blood immunity variables.