Effect of smokeless tobacco products on human oral bacteria growth and viability

Abstract

To evaluate the toxicity of smokeless tobacco products (STPs) on oral bacteria, seven smokeless tobacco aqueous extracts (STAEs) from major brands of STPs and three tobacco-specific N-nitrosamines (TSNAs) were used in a growth and viability test against 38 oral bacterial species or subspecies. All seven STAEs showed concentration-dependent effects on the growth and viability of tested oral bacteria under anaerobic culture conditions, although there were strain-to-strain variations. In the presence of 1 mg/ml STAEs, the growth of 4 strains decreased over 0.32–2.14 log10 fold, while 14 strains demonstrated enhanced growth of 0.3–1.76 log10 fold, and the growth of 21 strains was not significantly affected. In the presence of 10 mg/ml STAEs, the growth of 17 strains was inhibited 0.3–2.11 log10 fold, 18 strains showed enhanced growth of 0.3–0.97 log10 fold, and 4 strains were not significantly affected. In the presence of 50 mg/ml STAEs, the growth of 32 strains was inhibited 0.3–2.96 log10 fold, 8 strains showed enhanced growth of 0.3–1.0 log10 fold, and 2 strains were not significantly affected. All seven STAEs could promote the growth of 4 bacterial strains, including Eubacterium nodatum, Peptostreptococcus micros, Streptococcus anginosus, and Streptococcus constellatus. Exposure to STAEs modulated the viability of some bacterial strains, with 21.1–66.5% decrease for 4 strains at 1 mg/ml, 20.3–85.7% decrease for 10 strains at 10 mg/ml, 20.0–93.3% decrease for 27 strains at 50 mg/ml, and no significant effect for 11 strains at up to 50 mg/ml. STAEs from snuffs inhibited more tested bacterial strains than those from snus indicating that the snuffs may be more toxic to the oral bacteria than snus. For TSNAs, cell growth and viability of 34 tested strains were not significantly affected at up to 100 μg/ml; while the growth of P. micros was enhanced 0.31–0.54 log10 fold; the growth of Veillonella parvula was repressed 0.33–0.36 log10 fold; and the cell viabilities of 2 strains decreased 56.6–69.9%. The results demonstrate that STAEs affected the growth of some types of oral bacteria, which may affect the healthy ecological balance of oral bacteria in humans. On the other hand, TSNAs did not significantly affect the growth of the oral bacteria.

Smokeless tobacco impacts oral microbiota in a Syrian Golden hamster cheek pouch carcinogenesis model

“…High sugar content in STPs enhanced the growth of Lactobacillus casei and led to dental caries [25]. Our previous study showed that extracts from STPs affected the in vitro growth of some species of oral bacteria [26]. Taken together, these results suggest that STP may disrupt the ecological balance of oral microbiota; however, the impact of STPs on diversity and abundance of oral microbiota has not been well studied.…”

“…Our previous in vitro study showed similar results. Extracts from STPs could stimulate the growth of some bacteria at low concentration and inhibit the growth of some bacteria at high concentration [26]. These dose dependent effects might be due to the components of STPs, which contain high sugar content (added as sweetener) [27] and toxic compounds as well.…”

“…Our previous study showed that different species of bacteria had different responses to extracts of STPs. Some bacteria were inhibited or killed by STPs, while other bacteria could tolerate extracts of STPs [26]. Therefore, part of the changes in bacterial abundance in the 250 mg STP exposure group could be due to direct effects on specific bacteria in the microbial consortia of the oral microbiota and secondary responses due to the structural community changes in the oral microbiota caused by this STP.…”

In vitro effect of tuibur (tobacco brew) on the viability of human blood lymphocytes

“…21 A study on seven smokeless tobacco aqueous extracts showed a concentrationdependent effects on the growth and viability of oral bacteria cultured under anaerobic conditions. 22 These effects may be a result of increase superoxide anion production, lipid peroxidation, DNA fragmentation and DNA ladders caused by the use of chewing tobaccos. 23 Our result showed concentration dependent cell viability for the tuibur and nicotine treatment groups while the untreated negative control group showed 100% viability.…”

GC-MS Analysis and Cytotoxicity Evaluation of Shammah (Smokeless Tobacco) Samples of Jazan Region of Saudi Arabia as Promoter of Cancer Cell Proliferation

“…In addition to that, the use of smokeless tobacco is also associated with a wide range of adverse health issues, including cardiovascular diseases, weight loss, increased blood urea, and creatinine levels which seem to cause serious degenerative alterations and lead to periportal fibrosis in liver and edematous and calcified changes in renal glomerulus [7]. Aqueous extracts of ST hinder growths of some oral flora, which affect their balance, causing oxidative stress via degradation of nicotine into hydroxynicotine and cotinine-N-oxide inside the bacterium [8,9]. Furthermore, disruption of sperm-head morphology, decreased total sperm count, increased oxidative stress, and high genotoxic and germ cell toxic effects have been seen in animals treated with tobacco [10].…”