Bacterial Populations Associated with Smokeless Tobacco Products

Abstract

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 ؋ 10 6 CFU/g STP) and diversity of bacterial populations than snus (average of 8.33 ؋ 10 1 CFU/g STP) and some chewing tobacco products (average of 2.54 ؋ 10 5 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 tobaccospecific 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.

Smokeless tobacco products harbor diverse bacterial microbiota that differ across products and brands

“…These authors showed that bacteria from the families Staphylococcaceae , Aerococcaceae and Enterococcaceae were most abundant in moist snuff; bacteria from the families Bacillaceae , Staphylococcaceae and Lactobacillaceae were most abundant in dry snuff; and bacteria from the families Staphylococcaceae and Aerococcaceae were abundant in Toombak. Similarly, Han et al (2016) recently showed that bacteria from the genera Tetragenococcus , Carnobacterium , Lactobacillus , Geobacillus , Bacillus , and Staphylococcus were dominant in smokeless tobacco products tested using a 16S rRNA sequencing method. In addition, Han et al (2016) completed culture-based detection methods on the smokeless tobacco products and showed that the following species were most commonly isolated from the tested products: Bacillus pumilus, B. licheniformis, B. safensis and B. subtilis.…”

“…Similarly, Han et al (2016) recently showed that bacteria from the genera Tetragenococcus , Carnobacterium , Lactobacillus , Geobacillus , Bacillus , and Staphylococcus were dominant in smokeless tobacco products tested using a 16S rRNA sequencing method. In addition, Han et al (2016) completed culture-based detection methods on the smokeless tobacco products and showed that the following species were most commonly isolated from the tested products: Bacillus pumilus, B. licheniformis, B. safensis and B. subtilis. …”

The Bacterial Communities of Little Cigars and Cigarillos Are Dynamic Over Time and Varying Storage Conditions

“…Several recent studies using next-generation sequencing have characterized the bacterial communities in a variety of tobacco products, including smokeless tobacco (Han et al, 2016; Tyx et al, 2016; Smyth et al, 2017), cigarettes (Chopyk et al, 2017a, b) and little cigars (Chattopadhyay et al, 2019). Our group recently showed that cigarette tobacco was dominated by bacteria from the genera Pseudomonas , Pantoea , and Bacillus , many of which contain potentially pathogenic species – such as Pseudomonas putida —that cigarette smokers may be exposed to over time (Chopyk et al, 2017a, b).…”

Bacterial contamination of packaged smokeless tobacco sold in India

“…A total of 22 SLT products available in the market were analysed for contamination using bacterial culture. The number of brands to be included was based on previous studies conducted on SLT products in countries other than India [18][19][20] . All products were found to be contaminated with bacteria.…”