Microbial communities and gene contributions in smokeless tobacco products

Abstract

Smokeless tobacco products (STP) contain bacteria, mold, and fungi due to exposure from surrounding environments and tobacco processing. This has been a cause for concern since the presence of microorganisms has been linked to the formation of highly carcinogenic tobaccospecific nitrosamines. These communities have also been reported to produce toxins and other proinflammatory molecules that can cause mouth lesions and elicit inflammatory responses in STP users. Moreover, microbial species in these products could transfer to the mouth and gastrointestinal tract, potentially altering the established respective microbiotas of the consumer. Here, we present the first metagenomic analysis of select smokeless tobacco products, specifically US domestic moist and dry snuff. Bacterial, eukaryotic, and viral species were found in all tobacco products where 68% of the total species was comprised of Bacteria with 3 dominant phyla but also included 32% Eukarya and 1% share abundance for Archaea and Viruses. Furthermore, 693,318 genes were found to be present and included nitrate and nitrite reduction and transport enzymes, antibiotic resistance genes associated with resistance to vancomycin, β-lactamases, their derivatives, and other antibiotics, as well as genes encoding multi-drug transporters and efflux pumps. Additional analyses showed the presence of endo-and exotoxin genes in addition to other molecules associated with inflammatory responses. Our results present a novel aspect of the smokeless tobacco microbiome and provide a better understanding of these products' microbiology.

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

“…Furthermore, under optimal conditions N-nitrosation reaction of alkaloids with nitrite results in the formation of TSNAs (Wang et al, 2017). A few studies identified nitrogen metabolism genes in American STPs and Sudanese Toombak by whole metagenome and 16S rRNA gene metagenomics (Tyx et al, 2016;Rivera et al, 2020). Tyx et al (2016) observed that the nitrate reductase genes (narGHJI), nitrite reductase genes (nirABC) and nitrate/nitrite transporters genes were significantly abundant in American dry snuff products.…”

“…The spread of antibiotic resistance genes to oral microbiota of SLT users can be attributed to the practice of smokeless tobacco consumption (Lacoma et al, 2019). The whole metagenome sequencing and analysis of American-STPs showed the presence of several antibiotic resistance genes associated with resistance to β-lactam, penicillin, vancomycin, macrolides, aminoglycosides antibiotics, and other genes encode for multidrug transporters and efflux pumps (Rivera et al, 2020). The imputed metagenome of Indian-moist STPs like Q1, Q2, Q3, MS2, and S2 displayed a prevalence of antibiotic resistance genes having the potential to deactivate antibiotics.…”

“…Studies on the SLT associated bacteriome showed the presence of species belonging to clinically relevant bacterial classes like Actinobacteria (Corynebacterium, Mycobacterium, and Propionibacterium), Bacteroidia (Prevotella and Porphyromonas), Bacilli (Bacillus, Listeria, Staphylococcus, and Streptococcus), Chlamydiae, Clostridia (Clostridium), Fusobacteria (Fusobacterium and Streptobacillus), α-Proteobacteria (Brucella and Rickettsia), β-Proteobacteria (Neisseria and Spririllum), γ-Proteobacteria (Haemophilus and Pseudomonas), Spirochete (Borrelia and Leptospira) and Mollicutes (Mycoplasma) (Gholizadeh et al, 2016;Al-Hebshi et al, 2017;Monika et al, 2020). Furthermore, SLT-associated microbes can influence systemic inflammation and supplementary signaling pathways associated with oral cancer progression because they produce toxins and other proinflammatory molecules (Rivera et al, 2020;Sajid et al, 2021). Additionally, SLT-associated microbiota can be contaminated with pathogenic microbes and possibly a source of antibiotic resistance threat (Rivera et al, 2020).…”

“…Furthermore, SLT-associated microbes can influence systemic inflammation and supplementary signaling pathways associated with oral cancer progression because they produce toxins and other proinflammatory molecules (Rivera et al, 2020;Sajid et al, 2021). Additionally, SLT-associated microbiota can be contaminated with pathogenic microbes and possibly a source of antibiotic resistance threat (Rivera et al, 2020).…”

Shotgun metagenome sequencing of a Sudanese toombak snuff tobacco: genetic attributes of a high tobacco‐specific nitrosamine containing smokeless tobacco product

“…A presentation of the phylogenetic abundance at the highest level of taxonomy using the built-in IMG/M-ER generated phylogenetic abundance is presented in Table S1. The first notable aspect of this toombak metagenome is the absence of fungi, unlike domestic US moist snuff product, where fungi achieved some prominence (Rivera et al 2020). Fungi have been identified and studied in certain smokeless products, and have been found to be variable in abundance likely based on conditions of fermentation (Rivera and Tyx 2021;Vishwakarma and Verma 2021).…”