Characterization of Bacterial Communities in Selected Smokeless Tobacco Products Using 16S rDNA Analysis.
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ABSTRACT:
SUBMITTER: Tyx RE
PROVIDER: S-EPMC4718623 | biostudies-literature | 2016
REPOSITORIES: biostudies-literature
Publications
Characterization of Bacterial Communities in Selected Smokeless Tobacco Products Using 16S rDNA Analysis.
Tyx Robert E RE Stanfill Stephen B SB Keong Lisa M LM Rivera Angel J AJ Satten Glen A GA Watson Clifford H CH
PloS one 20160119 1
The bacterial communities present in smokeless tobacco (ST) products have not previously reported. In this study, we used Next Generation Sequencing to study the bacteria present in U.S.-made dry snuff, moist snuff and Sudanese toombak. Sample diversity and taxonomic abundances were investigated in these products. A total of 33 bacterial families from four phyla, Actinobacteria, Firmicutes, Proteobacteria and Bacteroidetes, were identified. U.S.-produced dry snuff products contained a diverse di ...[more]
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Project description:There are an estimated 8 million users of smokeless tobacco products (STPs) in the United States, and yet limited data on microbial populations within these products exist. To better understand the potential microbiological risks associated with STP use, a study was conducted to provide a baseline microbiological profile of STPs. A total of 90 samples, representing 15 common STPs, were purchased in metropolitan areas in Little Rock, AR, and Washington, DC, in November 2012, March 2013, and July 2013. Bacterial populations were evaluated using culture, pyrosequencing, and denaturing gradient gel electrophoresis (DGGE). Moist-snuff products exhibited higher levels of bacteria (average of 1.05 × 106 CFU/g STP) and diversity of bacterial populations than snus (average of 8.33 × 101 CFU/g STP) and some chewing tobacco products (average of 2.54 × 105 CFU/g STP). The most common species identified by culturing were Bacillus pumilus, B. licheniformis, B. safensis, and B. subtilis, followed by members of the genera Oceanobacillus, Staphylococcus, and Tetragenococcus. Pyrosequencing analyses of the 16S rRNA genes identified the genera Tetragenococcus, Carnobacterium, Lactobacillus, Geobacillus, Bacillus, and Staphylococcus as the predominant taxa. Several species identified are of possible concern due to their potential to cause opportunistic infections and reported abilities to reduce nitrates to nitrites, which may be an important step in the formation of carcinogenic tobacco-specific N'-nitrosamines. This report provides a microbiological baseline to help fill knowledge gaps associated with microbiological risks of STPs and to inform potential regulations regarding manufacture and testing of STPs.ImportanceIt is estimated that there 8 million users of smokeless tobacco products (STPs) in the United States; however, there are limited data on microbial populations that exist within these products. The current study was undertaken to better understand the potential microbiological risks associated with STP use and provide a baseline microbiological profile of STPs. Several bacterial species were identified that are of possible concern due to their potential to cause opportunistic infections. In addition, some species have abilities to reduce nitrates to nitrites, which may be an important step in the formation of carcinogenic tobacco-specific N'-nitrosamines. Overall, this report provides a microbiological baseline to help fill knowledge gaps related to the microbiological risks of STPs and to inform potential regulations regarding the manufacture and testing of STPs.
| S-EPMC5068160 | biostudies-literature
Project description: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 tobacco-specific nitrosamines. These communities have also been reported to produce toxins and other pro-inflammatory 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. KEY POINTS: • The findings presented will help understand microbial contributions to overall STP chemistries. • Gene function categorization reveals harmful constituents outside canonical forms. • Pathway genes for TSNA precursor activity may occur at early stages of production. • Bacteria in STPs carry antibiotic resistance genes and gene transfer mechanisms.
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Project description:Smokeless tobacco products contain numerous chemical compounds, including known human carcinogens. Other smokeless tobacco constituents, including bacteria, may also contribute to adverse health effects among smokeless tobacco users. However, there is a lack of data regarding the microbial constituents of smokeless tobacco. Our goal was to characterize the bacterial microbiota of different smokeless tobacco products and evaluate differences across product types and brands. DNA was extracted from 15 brands of smokeless tobacco products (including dry snuff, moist snuff, snus, and Swedish snus) and 6 handmade products (e.g., toombak) using an enzymatic and mechanical lysis approach. Bacterial community profiling was performed using PCR amplification of the V1-V2 hypervariable region of the 16S rRNA gene, followed by 454 pyrosequencing of the resulting amplicons and sequence analysis using the QIIME package. Total viable counts were also determined to estimate the number of viable bacteria present in each product. Average total viable counts ranged from 0 to 9.35 × 107 CFU g-1. Analysis of the 16S rRNA gene sequences revealed high bacterial diversity across the majority of products tested: dry snuff products where characterized by the highest diversity indices compared to other products. The most dominant bacterial phyla across all products were Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes. Significant differences in both bacterial community composition and in silico predicted gene content were observed between smokeless tobacco product types and between brands of specific smokeless tobacco products. These data are useful in order to comprehensively address potential health risks associated with the use of smokeless tobacco products.
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Project description:IntroductionAdequate evaluation of novel tobacco products must include investigation of consumers' psychological response to such products. Traditionally, subjective scales of product liking have been used to assess consumer acceptability of tobacco products. However, subjective scales may miss cognitive changes that can only be captured by direct neurophysiological assessment. The present investigation explored the viability of using electroencephalography (EEG), in combination with traditional subjective measures, to assess consumer acceptability of five smokeless tobacco products. Given previous work linking product liking to arousal/attentional (executive function) enhancement, we focused on EEG measures of attention/arousal to objectively characterize cognitive changes associated with tobacco product use.MethodsDuring five separate laboratory visits, smokeless tobacco users used Verve discs, Ariva dissolvables, Skoal snuff, Camel snus, or Nicorette lozenges. The N2 and P3b event-related potential components elicited by an oddball task were used to index attentional changes before/after product usage. Additionally, resting state alpha band EEG activity was analyzed before/after product usage to index cortical arousal.ResultsAlthough analyses of the subjective results provided limited inference, analyses of the electrophysiological measures, particularly the alpha suppression measure, revealed robust differences between products. Skoal elicited significantly enhanced alpha suppression compared to all four other products tested. Additionally, alpha suppression was found to correlate positively with subjective measures of satisfaction and psychological reward, but was unrelated to perceived aversion.ConclusionsThe present results provide evidence that electrophysiological measures can yield important insights into consumer acceptability of novel tobacco products and are a valuable complement to subjective measures.ImplicationsThis study is the first to employ a combination of electrophysiological measures and traditional subjective assays in order to assess the consumer acceptability of smokeless tobacco products. The results highlight the importance of adopting a multidimensional/multi-method approach to studying the consumer acceptability of tobacco products.
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Project description:IntroductionSmokeless tobacco products such as snuff and snus are used worldwide. However, little is known about the systemic and cardiovascular toxicity of smokeless tobacco exposure.MethodsBiomarkers of endothelial activation and injury, immune functions, platelet activation and insulin resistance were measured in 8-week old male C57BL/6 mice exposed to commercial snuff, CRP-2 reference snuff, commercial snus, CRP-1 reference snus, and nicotine in drinking water (100 µg/mL) for 4, 12, and 24 weeks.ResultsTwenty-four weeks of exposure to smokeless tobacco products or nicotine significantly decreased the levels of circulating Flk+/Sca+ endothelial progenitor cells. Twelve and 24 weeks of exposure to all the smokeless tobacco products and nicotine significantly decreased the levels of circulating CD19+ B cells, CD4+ T cells, CD8+ T cells, and CD11b+ monocytes, whereas 4 weeks of exposure to Camel snus and Copenhagen snuff significantly depleted the levels of peripheral blood CD19+ B cells and CD11b+ monocytes. Twenty-four weeks of exposure to smokeless tobacco products or nicotine significantly decreased plasma IFNγ levels. However, plasma TNFα levels were significantly increased in mice exposed to Copenhagen snuff or nicotine for 24 weeks. This was accompanied by a five to sevenfold increase in the hepatic expression of TNFα. Neither smokeless products nor nicotine affected plasma lipoproteins, platelet activation, or systemic insulin sensitivity.ConclusionsChronic exposure to snuff and snus suppresses circulating levels of EPCs, endothelial microparticles and immune cells, but increases plasma TNF-α levels. These effects of smokeless tobacco products are attributable, at least in part, to nicotine.ImplicationsExposure to smokeless tobacco products results in the depletion of endothelial progenitor cells, which may impair the endothelium repair. Suppression of the circulating levels of immune cells upon exposure to smokeless tobacco products may increase the susceptibility to secondary infection. Increased formation of proinflammatory cytokines such as TNFα by nicotine or Copenhagen snuff may lead to vascular inflammation and thereby exacerbate atherogenesis.
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Project description:The major components of 70 brands of smokeless tobacco products (STPs) from Sweden and the US were determined to provide greater understanding of the general chemical composition of these products. Various styles of STPs were examined: loose and portion snus from Sweden, and chewing tobacco, dry snuff, moist snuff, hard pellet, soft pellet and plug from the US. The components analysed were major STP components such as water, nicotine, sugars, humectants, sodium ions, chloride ions and ash. The relative quantities of the components varied significantly between different styles of STP. The major component of moist snuff and Swedish loose snus is water. With Swedish portion snus water and pouch material comprise more than half of the product mass; with chewing tobaccos water and sugars comprise around 60% of the products. With these STPs, tobacco was a minor component (30-35%) of the product mass. By way of contrast, tobacco comprised the majority (around 70-90%) of the product mass with dry snuff, hard pellet and soft pellet products. Additives such as sugars, propylene glycol, glycerol, and sodium chloride comprised up to around 12% of the STPs, except for plug and chewing tobaccos where sugars comprised 15-30% by mass of the STP on average. Significant disagreements were found amongst alternative methods of determining water/moisture content for STPs. In particular the oven method, commonly used to determine moisture in tobacco, gave significantly higher values than the Karl Fischer water method when propylene glycol was present. Smaller but similar differences were found using the Near-Infrared method. Choice of measurement technique has important consequences for accuracy of toxicant levels when reporting on a dry-weight basis, a commonly used parameter in smokeless tobacco research and emerging regulatory standards. Conversion to a DWB was also found to produce a preferential bias between and within different STP categories in favour of drier products. These data provide greater understanding of differences in the compositions of contemporary smokeless tobacco products, and demonstrate challenges associated with conversion of actual product contents to dry weight basis values.
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