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 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.

中文翻译：

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无烟烟草制品中的微生物群落和基因贡献

摘要

由于暴露于周围环境和烟草加工，无烟烟草产品 (STP) 含有细菌、霉菌和真菌。这一直是一个令人担忧的问题，因为微生物的存在与高度致癌的烟草特有亚硝胺的形成有关。据报道，这些社区还会产生毒素和其他促炎分子，这些分子会导致口腔病变并引发 STP 使用者的炎症反应。此外，这些产品中的微生物种类可能会转移到口腔和胃肠道，可能会改变消费者已建立的相应微生物群。在这里，我们展示了对精选无烟烟草产品，特别是美国国内湿鼻烟和干鼻烟的首次宏基因组分析。细菌、真核、具有 3 个优势门的细菌，但也包括 32% 的真核生物和 1% 的古细菌和病毒共享丰度。此外，发现存在 693,318 个基因，包括硝酸盐和亚硝酸盐还原和转运酶、与万古霉素、β-内酰胺酶及其衍生物和其他抗生素抗性相关的抗生素抗性基因，以及编码多药转运蛋白和外排的基因泵。其他分析表明，除了与炎症反应相关的其他分子外，还存在内毒素和外毒素基因。我们的结果展示了无烟烟草微生物组的一个新方面，并提供了对这些产品微生物学的更好理解。

关键点

•所呈现的发现将有助于了解微生物对整体 STP 化学的贡献。

•基因功能分类揭示了规范形式之外的有害成分。

• TSNA 前体活性的通路基因可能出现在生产的早期阶段。

• STP 中的细菌携带抗生素抗性基因和基因转移机制。