Comparison of oral microbiome profiles in stimulated and unstimulated saliva, tongue, and mouth-rinsed water

Abstract

Epidemiological studies using saliva have revealed relationships between the oral microbiome and many oral and systemic diseases. However, when collecting from a large number of participants such as a large-scale cohort study, the time it takes to collect saliva can be a problem. Mouth-rinsed water, which is water that has been used to rinse the oral cavity, can be used as an alternative method for collecting saliva for oral microbiome analysis because it can be collected in a shorter time than saliva. The purpose of this study was to verify whether mouth-rinsed water is a suitable saliva substitute for analyzing the oral microbiome. We collected samples of mouth-rinsed water, stimulated saliva, unstimulated saliva, and tongue coating from 10 systemic healthy participants, and compared the microbial diversity and composition of the samples using next-generation sequencing of 16S rRNA-encoding genes. The results showed that the microbial diversity of mouth-rinsed water was similar to that of unstimulated and stimulated saliva, and significantly higher than that of tongue-coating samples. The microbial composition at the species level of mouth-rinsed water also showed a very high correlation with the composition of unstimulated and stimulated saliva. These results suggest that the mouth-rinsed water is a suitable collection method instead of saliva for oral microbiome analysis.

Association between the microbiomes of tonsil and saliva samples isolated from pediatric patients subjected to tonsillectomy for the treatment of tonsillar hyperplasia

“…Recent advances in sequencing technology and metagenomics have expanded our knowledge of the composition and association of the oral microbiome with human health and disease. The oral cavity microbiome has generally been examined through the collection of oral rinse samples, including saliva, but it remains to be established whether saliva provides an accurate representation of the microbiome of the oral cavity 27,28 . Given that the human oral cavity is composed of various subsites, including the teeth, gingival sulcus, tongue, hard and soft palates, and tonsils, which provide appropriate space for colonization but slightly different environments for microorganisms, the salivary microbiome profile may not be correlated with those of other subsites of the oral cavity.…”

“…The microbiome profile of saliva appears to be more stable than that of tonsils. Saliva is constantly secreted from salivary glands into the oral cavity, containing a diverse bacterial population, while the microbial community in tonsils is mainly colonized in the recessed epithelium of deeply branched crypts 27,35 . Therefore, saliva continuously secreted from various oral sites contains diverse bacteria, but the range in tonsils is lower since the microbial populations stagnate in the crypts and remain limited.…”

Comparison of oral microbiome profiles in 18-month-old infants and their parents

“…Saliva of infants were collected by sucking saliva accumulated in the oral cavity using a swab stick. Parent’s saliva samples were collected as mouth-rinsed water 36 . Briefly, participants rinsed their mouth vigorously with 3 mL sterilised water for 10 s, and then spat into a sterilised specimen tube.…”

Characterization of the microbiomic association between tonsil and saliva isolated from Korean children subjected to tonsillectomy using 16S rRNA sequencing: a pilot study

“…Recent advances in sequencing technology and metagenomics have expanded our knowledge of the composition and association of the oral microbiome with human health and disease. The oral cavity microbiome has generally been examined by collecting oral rinse samples, including saliva, but it remains to be established whether saliva provides an accurate representation of the microbiome of the oral cavity [18]. Given that the human oral cavity is composed of various subsites, including teeth, gingival sulcus, tongue, hard and soft palates, and tonsils, which provide appropriate space for colonization but slightly different environments for microorganisms, the salivary microbiome profile may not be correlated with those of other subsites of the oral cavity.…”

“…profile of saliva appears more stable relative to that of tonsils. Saliva is constantly secreted from salivary glands into the oral cavity containing a diverse bacterial population while the microbial community in tonsils is mainly colonized in the recessed epithelium of deeply branched crypts [18,24]. Therefore, saliva continuously secreted from various oral sites contains diverse bacteria but the range in tonsils is lower since the microbial populations stagnate in the crypts and remain limited.…”