Effect of peanut stilbenoids, arachidin-1 and arachidin-3, on Streptococcus mutans growth and acid production.

In this study we evaluated the effect of prenylated peanut stilbenoids on the growth, biofilm accumulation and acid production of the dental caries pathogen Streptococcus mutans. Prior research with the non-prenylated stilbenes, resveratrol and piceatannol, has shown that these molecules are active against S. mutans. Here we sought to determine if the addition of a prenyl group to the stilbene backbone increased anti-S. mutans activities. Two prenylated stilbenes, arachidin-1 and arachidin-3, were produced using a peanut hairy root production system. Compared to resveratrol and piceatannol, both arachidin-1 and arachidin-3 led to greater inhibition of S. mutans planktonic growth. This effect also led to reduced biofilm formation, by inhibiting growth, instead of a specific action against biofilm cells. Lastly, sub-MIC concentrations of arachidin-3 reduced the acid production of S. mutans above the 'critical pH' that leads to tooth enamel erosion. In summary, stilbenoids have anti-S. mutans activity, and prenylation enhances this activity.

Removal of biofilms from tracheoesophageal speech valves using a novel marine microbial deoxyribonuclease.

OBJECTIVE: The growth of biofilms on tracheoesophageal speech valves shortens their life span and produces a reservoir of pathogens that may infect the respiratory tract. The authors have discovered a novel nontoxic deoxyribonuclease, NucB, from a marine isolate of Bacillus licheniformis that is effective at dispersing a variety of mono and mixed-species bacterial biofilms. The aim of this preliminary study was to determine whether NucB could also disrupt and remove mixed-species biofilms from tracheoesophageal speech valves. STUDY DESIGN: Laboratory-based treatment and analysis of discarded tracheoesophageal speech valves. SETTING: University human biology laboratory and the Department of Speech and Language Therapy at a tertiary referral hospital. SUBJECTS AND METHODS: Seventeen ex vivo tracheoesophageal speech valves fouled with natural human biofilms were collected and divided into 2 equal parts. One half was treated with NucB and the other half with a control buffer solution. Biofilm removal was measured by microscopy and by culture of dispersed biofilm organisms on agar plates. RESULTS: Significantly more organisms were released from biofilms using NucB than with buffer solution alone. On nonselective medium, more organisms were cultured in 11 samples (65%, n = 17, P < .05). Using growth media favoring fungi, more organisms were cultured in 14 samples (82%, n = 17, P < .05). CONCLUSION: The nontoxic deoxyribonuclease NucB was effective in releasing more microorganisms from biofilms on tracheoesophageal speech valves. This reflects its potential ability to break up and disperse these biofilms. Future studies will aim to develop NucB as a novel agent to prolong the life span of tracheoesophageal speech valves, thus reducing health care costs.