Fig.1.

Box plots showing the relative abundance of the most dominant bacterial phyla and the Firmicutes/Bacteroidetes ratio in adult and elderly groups. a The four dominant bacterial phyla. Bacteroidetes was significantly higher in elderly subjects (p = 0.019), and Actinobacteria was significantly higher in adult subjects (p = 0.001). b The Firmicutes/Bacteroidetes ratio. The F/B ratio of the adult and elderly groups was significantly different (p = 0.01). Comparisons between groups were performed using the Mann–Whitney U test. The darker box represents the ratio of the 25th to 50th percentile. The lighter box represents the ratio of the 50th to 75th percentile. The horizontal line separating the two boxes is the 50th percentile. *p < 0.05, *p < 0.01