Smokeless tobacco mediated alterations on the prevalence of oral pathogens and interactions of tobacco-specific nitrosamines (TSNAs) with host proteins

Abstract

Objective

Smokeless tobacco (SLT) product consumption is a major public health concern, especially in Southeast Asian countries, and a risk factor for oral cancer. Interference of host-oral microbiota homeostasis can promote oral cancer progression. SLT use can induce oral microbial population alterations that can contribute to oral pathologies including oral cancer.

Methods

In this study, we have determined the clinically relevant bacterial phyla and pathogens in the SLT users’ oral cavity (n = 95) and non-users (n = 85). Further, we checked the interaction of tobacco-associated toxic chemicals with the host proteins using the STITCH tool (http://stitch.embl.de/).

Results

We observed that the pathogens like Candida sp., Chlamydia trachomatis, and Human papillomavirus were significantly high in SLT users, whereas the occurrence of Trichomonas vaginalis was high in non-users. Further, the abundance of bacterial phyla including Actinobacteria, Bacteroidetes, and Fusobacteria, was significantly elevated in SLT users whereas phyla Proteobacteria prevalence was diminished in SLT users compared to non-users. Additionally, we observed that several host proteins including Cytochrome-P450, UDP-glucuronosyltransferase, and nicotinic acetylcholine receptors were showing strong interactions with toxic compounds present in SLT like nicotine, NNK, NNAL, NNN, and NAB.

Conclusions

These results indicate that SLT consumption can alter the oral bacterial and viral population and influence several proteins in SLT users. Therefore, enrichment of pathogenic bacteria along with depletion of beneficial bacteria can contribute to oral pathologies. This study will assist clinically in connecting the missing dots of pathogen population enrichment in the oral cavity of SLT users due to chewing of SLT products.