Bacteriome of Moist Smokeless Tobacco Products Consumed in India With Emphasis on the Predictive Functional Potential

Abstract

Smokeless tobacco products (STPs) carry assorted microbial population that contributes to carcinogens synthesis like tobacco-specific nitrosamines (TSNAs). Extensive exploration of microbiota-harboring STPs is required to understand their full carcinogenic potential. Here, we applied 16S rRNA gene sequencing to investigate bacteriome present in moist STPs immensely consumed in India (Khaini, Moist-snuff, Qiwam, and Snus). Further, the functional metagenome was speculated by PICRUSt (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) to assign the abundance of genes related to nitrogen metabolism, bacterial toxins, antibiotic drug resistance and other pro-inflammatory molecules. Highly diverse bacterial communities were observed in all moist STPs. Taxonomic analysis revealed a total of 549 genera belonging to four major phyla Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria. Overall, the core bacterial genera Acinetobacter, Bacillus, Prevotella, Acetobacter, Lactobacillus, Paracoccus, Flavobacterium, and Bacteroides were significantly abundant in moist STPs. Elevated moisture-holding products like Moist-snuff and Qiwam harbor rich bacterial species diversity and showed similar bacteriome composition. Furthermore, Qiwam products showed the highest level of genes associated with nitrogen metabolism, antibiotic resistance, toxins, and pro-inflammation (predicted by PICRUSt) which can contribute to the synthesis of TSNAs and induction of oral cancer. The present broad investigation of moist STPs-associated bacteriome prevalence and their detailed metabolic potential will provide novel insight into the oral carcinogenesis induced by STPs.

Altered oral microbiome in Sudanese Toombak smokeless tobacco users carries a newly emerging risk of squamous cell carcinoma development and progression

“…Smokeless tobacco use has been found to both reduce 66 , 67 and enrich Actinomyces growth 68 . Actinomyces has also been found in abundance in moist Indian smokeless tobacco products 69 . Actinomyces massiliensis ( p = 0.016) was abundant in the buccal microbiome of Toombak users while Actinomyces graevenitzii was found to be enriched in the tongue in both users and non-users of Toombak.…”

Characterization of physiochemical parameters & their effect on microbial content of smokeless tobacco products marketed in north India

“…The moisture content is another product characteristic that is regulated by the manufacturer. High moisture content favours the growth of microbes such as bacteria, fungi and viruses 19 26 27 . The presence of microorganisms and their metabolic activities has been linked to the conversion of nicotine and other tobacco alkaloids to highly carcinogenic TSNAs by nitrosation reaction 28 29 .…”

“…high moisture content does not influence the levels of free nicotine. Further, our previous studies determined the presence of a complex diversity of microbes (both bacterial and fungal) in Indian SLT products 17 18 19 . Interestingly, the SLTs having higher moisture content exhibited elevated levels of microbes, both in terms of diversity and number, which is corroborated with the previous studies 33 .…”

“…Estimation of bacterial and fungal diversity : As described in the previous studies performed, the V 3 -V 4 region of 16S rDNA and the ITS1 amplicon-sequencing techniques were used to identify the bacterial and fungal diversity by estimating operational taxonomic units (OTUs), respectively, of 22 SLT products 17 18 19 .…”

Comprehensive clinical assays for molecular diagnostics of gliomas: the current state and future prospects

“…Biokart India provides transcriptome and genome sequencing, but does not describe properly the NGS platform used for these services. According to available publications, they have in use Illumina Miseq ( Sajid et al, 2021 ) ( Figure 4 ; Supplementary Table S2 ).…”