Effect of nicotine on growth and metabolism of Streptococcus mutans.
Streptococcus mutans is a key contributor to dental caries. Smokers have a higher number of caries-affected teeth than do nonsmokers, but the association among tobacco, nicotine, caries, and S. mutans growth has not been investigated in detail. Seven S. mutans strains--UA159, UA130, 10449, A32-2, NG8, LM7, and OMZ175--were used in the present study. The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), minimum biofilm inhibitory concentration (MBIC), planktonic cell growth, biofilm formation, metabolism, and structure (determined using scanning electron microscopy) of the seven strains treated with different concentrations of nicotine (0-32 mg ml(-1)) were investigated. The MIC, MBC, and MBIC were 16 mg ml(-1) (0.1 M), 32 mg ml(-1) (0.2 M), and 16 mg ml(-1) (0.1 M), respectively, for most of the S. mutans strains. Growth of planktonic S. mutans cells was significantly repressed by 2.0-8.0 mg ml(-1) of nicotine. Biofilm formation and metabolic activity of S. mutans was increased in a nicotine-dependent manner up to 16.0 mg ml(-1) of nicotine. Scanning electron microscopy revealed that S. mutans treated with a high concentration of nicotine a had thicker biofilm and more spherical bacterial cells. In summary, nicotine enhances S. mutans biofilm formation and biofilm metabolic activity. These results suggest that smoking can increase the development of caries by fostering increased formation of S. mutans biofilm on tooth surfaces.
Department of Oral Biology and Tobacco Cessation and Biobehavioral Group, School of Dentistry, Indiana University, IN, USA.
Ruijie
R
Huang
Mingyun
M
Li
Richard L
RL
Gregory
D000704:Analysis of Variance; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D002478:Cells, Cultured; D003731:Dental Caries / Q000139:chemically induced*; D005731:Ganglionic Stimulants / Q000009:adverse effects / Q000494:pharmacology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D008855:Microscopy, Electron, Scanning; D009538:Nicotine / Q000009:adverse effects / Q000494:pharmacology*; D012907:Smoking / Q000009:adverse effects*; D013295:Streptococcus mutans / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D013778:Tetrazolium Salts
D005731:Ganglionic Stimulants; D013778:Tetrazolium Salts; D009538:Nicotine