Unraveling the human salivary microbiome diversity in Indian populations

Abstract

The importance of studying the salivary microbiome has been highlighted for its connection to health and disease and as a potential tool for supplementing human genetic diversity studies. While the salivary microbiome has been studied in various world populations, Indian populations have not been examined. We therefore analyzed microbiome diversity in saliva samples from 92 volunteers from eight different sampling locations in India by amplifying and sequencing variable regions (V1 and V2) of the bacterial 16S rRNA gene. The results showed immense bacterial richness in Indian populations; we identified 165 bacterial genera and 785 unique Operational Taxonomic Units (OTUs), with substantial sharing among the populations. There were small, but significant correlations in the abundance of bacterial genera in sampling locations from the same geographic region. Most of the core OTUs detected were also observed previously in other populations, but Solobacterium spp., Lachnoanaerobaculum spp. and Alloprevotella spp. were observed to be a component of the saliva microbiome unique to Indian populations. Importantly, nine bacterial genera were observed that were not listed in the Human Oral Microbiome Database (HOMD). These results highlight the importance of analyzing underrepresented populations like those of India.

Trick or Treating in Forensics—The Challenge of the Saliva Microbiome: A Narrative Review

“…A particular signature of ethnicity in oral microbiome was also underlined by Sarkar et al [ 28 ] in 2017, when they analysed microbiome diversity in saliva samples collected from 92 healthy volunteers, coming from eight different geographical locations in India. These different locations represented three geographic regions in India.…”

“…The lack of complete and wider information collection in experimental studies could compromise the possibility of gathering really informative data (i.e., useful to identify likely suspects in forensic contexts) from saliva microbiome analysis. For example, several studies published up till now have shown that salivary microbial composition can be related to the similar socio-economic background, culture, lifestyle, and food habits, which often characterize people coming from the same region [ 25 , 26 , 27 , 28 ]. In fact, factors such as food habits, which vary between different geographical locations, could contribute to the shaping of microbiome composition.…”

Potential Associations Among Alteration of Salivary miRNAs, Saliva Microbiome Structure, and Cognitive Impairments in Autistic Children

“…MiRnome and microbiome dysregulation in saliva of ASD patients was previously reported by other groups, but there is only a partial concordance with the data presented here [ 47 , 59 , 60 , 61 ]. The salivary microbiome structure in human beings is strongly affected by the geographical, climatic and ethnic origin of samples [ 62 , 63 , 64 ]. This could be due to the different ratio of dietary protein/ carbohydrate intake that, in turn, modulates salivary pH [ 65 ].…”

Akkermansia muciniphila in the Human Gastrointestinal Tract: When, Where, and How?

“…Several studies found a high abundance of the phyla Firmicutes, Proteobacteria, Bacteroidetes, and Actinobacteria, with Streptococcus (belonging to the phylum Firmicutes) being the most abundant genus [ 60 , 61 ]. The presence of Verrucomicrobia in the oral cavity is often not described [ 60 , 61 , 62 , 63 , 64 ]. However, the presence of Akkermansia -like sequences was found in the oral cavity of a choledocholithiasis patient [ 65 ].…”