*3.4. Candidates for Core Microbiome and Core-Microbiome Analysis*

Table 1 shows the bacterial species detected in more than 90% of subjects. Thirteen species were detected in all subjects. Among these 13 species, eight species were from the *Streptococcus* genus. These species represent potential candidates for the core oral microbiome. These 13 species are visualized using a phylogenetic tree and core heatmap in Figure 3.


**Table 1.** Bacterial species detected in more than 90% of subjects.

**Figure 3.** Core visualization: (**A**) phylogenetic tree and (**B**) core heatmap of 13 species detected in all subjects.

According to Figure 3, eight species of *Streptococcus* were not adjacent. *Streptococcus sinensis* and *Streptococcus pneumoniae* were highly prevalent and abundant species.
