Tobacco & Nicotine Products
Influence of brand, mentholation and storage conditions on the bacterial microbiota of cigarette tobacco
(School of Public Health (UMD) Maryland Institute for Applied Environmental Health Doctoral Student)
Cigarettes are home to complex microbial ecosystems. However, the bacterial dynamics of the cigarette microenvironment have been left largely unexplored, despite their critical implications with regard to the production of tobacco-specific nitrosamines. To address this knowledge gap, we conducted time series experiments with five different commercially-available brands of cigarettes, which were either commercially, experimentally or user-mentholated. The products were incubated under three different temperatures and relative humidities to mimic potential storage conditions (i.e. pocket, refrigerator and ambient). Overall, 360 samples were collected over the course of two weeks and total DNA was extracted, PCR amplified for the V3-V4 hypervariable regions of the 16S rRNA gene and sequenced using Illumina MiSeq. A subset of samples were also analyzed via liquid chromatography with tandem mass spectrometry for N'- nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). Comparative analyses of the bacterial community profiles from these five products revealed core bacterial operational taxonomic units (OTUs) that occurred in all samples, including opportunistic pathogens: Pseudomonas oryzihabitans and Pseudomonas putida. Beta-diversity analysis revealed bacterial composition differences by brand, mentholation state and manufacturer’s lot. The user-mentholated products saw the largest temporal shifts in alpha-diversity and the abundance of the major taxonomic groups corresponding to experimental conditions and mentholation state. In addition, the user- and commercially-mentholated products displayed a significant increase in NNN levels at the pocket temperature. These data suggest that manufacturing manipulations and user behavior may directly impact the microbiota (including bacterial pathogens) of cigarette products, which may have implications for public health.