Distal gut microbiota of adolescent children is different from that of adults

Abstract

Human intestinal microbiota plays a number of important roles in human health and is also implicated in several gastrointestinal disorders. Although the diversity of human gut microbiota in adults and in young children has been examined, few reports of microbiota composition are available for adolescents. In this work, we used Microbiota Array for high-throughput analysis of distal gut microbiota in adolescent children 11-18 years of age. Samples obtained from healthy adults were used for comparison. Adolescent and adult groups could be separated in the principal components analysis space based on the relative species abundance of their distal gut microbiota. All samples were dominated by class Clostridia. A core microbiome of 46 species that were detected in all examined samples was established; members of genera Ruminococcus, Faecalibacterium, and Roseburia were well represented among core species. Comparison of intestinal microbiota composition between adolescents and adults revealed a statistically significantly higher abundance of genera Bifidobacterium and Clostridium among adolescent samples. The number of detected species was similar between sample groups, indicating that it was the relative abundances of the genera and not the presence or absence of a specific genus that differentiated adolescent and adult samples. In summary, contrary to the current belief, this study suggests that the gut microbiome of adolescent children is different from that of adults.

Figure 1. Results of the principal components analysis of the microarray dataset

Principal component 1 values for each sample are plotted on the X axis and principal component 2 values are plotted on the Y axis. aHLT – healthy adult samples (n=10); kHLT – healthy adolescent samples (n=22).

Figure 2. Distribution of microbial species detection and abundance among adolescent and adult samples

The main figure displays a group scatter plot with the X axis listing different bacterial classes and the Y axis representing relative combined abundance of the members of each class in individual samples. Note that the Y axis is shown in linear scale separated into 3 segments. aHLT – healthy adult samples (triangle; n=10); kHLT – healthy adolescent samples (diamond; n=22). Horizontal bars represent weighted means of the abundance of each class among all samples of a particular group. Three sets of values below the scatter plot show (i) the number of samples in which members of each class were detected (“samples”); (ii) an average number of detected species of each class per sample (“avg det”); and (iii) an average combined relative abundance (weighted mean) of class members in each sample (“avg abnd”).

Figure 3. Distribution of genus relative abundances among samples

Different experiments are plotted as columns; 115 analysed genera are plotted as rows. Relative abundances of each genus are plotted using a gradient scale as shown in the legend. aHLT – healthy adult samples; kHLT – healthy adolescent samples. Vertical line separates aHLT and kHLT samples. The 12 most abundant genera are shown on the right side; numbers represent relative average abundance of each genus (weighted mean) in aHLT and kHLT samples, respectively. Genus assignments to four most abundant phyla are shown on the left side of the image. Sample kHLT07 lacking members of Bacteroidetes is highlighted.