Interaction of Oral and Toothbrush Microbiota Affects Oral Cavity Health

Abstract

Tooth brushing is necessary to maintain oral health. Little research has been carried out to explore microbial diversity in toothbrushes and to study the potential impact of these bacteria on human health. In the present study, 20 participants were enrolled, and the microbial diversity in their oral cavity and toothbrushes was investigated using high-throughput sequencing. Our results indicate that 1,136 and 976 operational taxonomic units (OTUs) were obtained from groups CB (samples from toothbrushes of participants using traditional Chinese medicinal toothpaste) and AB (samples from toothbrushes of those using antibacterial toothpaste), respectively. The pathogens Acinetobacter baumannii, Staphylococcus aureus, and Candida albicans were identified on toothbrushes. The presence of these pathogens increases the chance for the host to get infectious diseases, neurodegenerative diseases, cardiovascular diseases, and cancers. Moreover, our in vitro results indicate that traditional Chinese medicinal toothpaste and antibacterial toothpaste can not only inhibit the growth of pathogens but also markedly inhibit the growth of probiotics Lactobacillus salivarius and Streptococcus salivarius. Therefore, the inhibitory effect of toothpaste on probiotics, together with the existence of pathogens in toothbrushes, indicates a potential risk of tooth brushing for people in a sub-healthy state.

Keywords: brushing teeth; high-throughput sequencing; oral microbiota; pathogens; toothbrush.

Figure 1

Indices of oral bacterial diversity. (A) Calculations of Shannon indices among groups CO, CB, AO, and AB; (B) calculations of species observed among groups CO, CB, AO, and AB; (C) scalar Venn diagrams among groups CO, CB, AO, and AB; (D) PLS-DA analysis of groups CO, CB, AO, and AB. CO, oral microbiota of people using traditional Chinese medicinal toothpaste (n = 10); CB, microbiota of toothbrushes corresponding to group CO (n = 10); AO, oral microbiota of people using antimicrobial toothpaste (n = 10); AB, microbiota of toothbrushes corresponding to group AO (n = 10).

Figure 2

Ratios of the known bacteria in groups CO, CB, AO, and AB at the phylum level (A). Relative abundance of Bacteroidetes (B), Firmicutes (C), and Proteobacteria (D) in groups CO, CB, AO, and AB. CO, oral microbiota of people using traditional Chinese medicinal toothpaste (n = 10); CB, microbiota of toothbrushes corresponding to group CO (n = 10); AO, oral microbiota of people using antimicrobial toothpaste (n = 10); AB, microbiota of toothbrushes corresponding to group AO (n = 10). Data are presented as means ± SD; *P < 0.05 by Kruskal–Wallis.

Figure 3

Ratios of the known bacteria in groups CO, CB, AO, and AB at the genus level. (A) Relative abundance of Streptococcus (B), Acinetobacter (C), Burkholderia (D), Stenotrophomonas (E), and Prevotella (F) in groups CO, CB, AO, and AB. CO, oral microbiota of people using traditional Chinese medicinal toothpaste (n = 10); CB, microbiota of toothbrushes corresponding to group CO (n = 10); AO, oral microbiota of people using antimicrobial toothpaste (n = 10); AB, microbiota of toothbrushes corresponding to group AO (n = 10). Data are presented as means ± SD; *P < 0.05 by Kruskal–Wallis.

Figure 4

Relative abundance of groups CO, CB, AO, and AB using PICRUSt based on the KEGG database. Classification based on cellular process—transport and catabolism (A), cell motility (B). Classification based on human disease—neurodegenerative diseases (C), infectious diseases (D), cancers (E), cardiovascular diseases (F). CO, oral microbiota of people using traditional Chinese medicinal toothpaste (n = 10); CB, microbiota of toothbrushes corresponding to group CO (n = 10); AO, oral microbiota of people using antimicrobial toothpaste (n = 10); AB, microbiota of toothbrushes corresponding to group AO (n = 10). Data are presented as means ± SD; *P < 0.05 by Kruskal–Wallis.

Figure 5

Inhibitory action of traditional Chinese medicinal toothpaste and antimicrobial toothpaste on isolated strains. CTL: PBS buffer; C, 20% concentration of traditional Chinese medicinal toothpaste; A, 20% concentration of antimicrobial toothpaste. CO, oral microbiota of people using traditional Chinese medicinal toothpaste (n = 10); CB, microbiota of toothbrushes corresponding to group CO (n = 10); AO, oral microbiota of people using antimicrobial toothpaste (n = 10); AB, microbiota of toothbrushes corresponding to group AO (n = 10). *P < 0.05, **P < 0.01, ^#P < 0.05, ^##P < 0.01. Data are presented as means ± SD; *P < 0.05 vs. control group (CTL group) by ANOVA, ^#P < 0.05 vs. C group by Kruskal–Wallis.

Figure 6

Flow chart of the present study. Toothbrush and oral samples were obtained from the participants treated with traditional Chinese medicinal toothpaste and antibacterial toothpaste, respectively. A high-throughput sequencing method was used to analyse species richness. Genera showing a significant increase compared with other groups are shown with ↑; those showing a highly significant increase are shown with ↑↑. The increased risks of human disease for each group are shown.