IADR Abstract Archives
Nisin and NaF Synergistically Inhibit Streptococcus Mutans
Objectives: Streptococcus mutans is the primary etiologic agent of dental caries. Nisin, a bacteriocin, has been demonstrated to be microbicidal against gram positive bacteria. Fluoride is widely used as a classic anti-caries agent. The purpose of this study is to explore the synergistic effect of Nisin and sodium fluoride on S. mutans.
Methods: Microbroth assay was used to analyze the minimum bactericidal concentration of Nisin and NaF. Meanwhile, the checkerboard method and fractional inhibitory concentration (FIC) were used to evaluate the synergistic effect. Analyze the effect of drugs on S. mutans acid production by change of pH. Crystal violet biofilm biomass assay was performed to evaluate the potential effects of drugs. CLSM was used to observe the morphology and the structure of biofilm. Furthermore, we performed reverse transcription quantitative polymerase chain reaction (qRT-PCR) and lactate dehydrogenase enzymatic methods.
Results: Results showed that either Nisin at concentration of 20mg/ml or NaF at 1.2mg/ml inhibited the growth of S. mutans. Nisin revealed synergism with NaF with FIC indexes ≤ 0.5. NaF and Nisin can inhibit the acid production of S. mutans strongly. The effect is stronger when both are present. It was found that the combination of the two drags at sub-inhibitory concentrations had a significant inhibitory effect on the formation of biofilm. Moreover, mixed drugs produced a stronger bactericidal effect on S. mutans biofilm compared with any drugs alone by CLSM. In addition, Nisin decreased the expression of genes related to extracellular polysaccharide (EPS) synthesis (gtfB, gtfC, gtfD and spaP) and acidogenicity (ldh) , and the effect is more obvious under the action of NaF.
Conclusions: In conclusion, Nisin and NaF have a good synergistic effect against S. mutans and may be used as an effective drug combination for the prevention of dental caries.
Methods: Microbroth assay was used to analyze the minimum bactericidal concentration of Nisin and NaF. Meanwhile, the checkerboard method and fractional inhibitory concentration (FIC) were used to evaluate the synergistic effect. Analyze the effect of drugs on S. mutans acid production by change of pH. Crystal violet biofilm biomass assay was performed to evaluate the potential effects of drugs. CLSM was used to observe the morphology and the structure of biofilm. Furthermore, we performed reverse transcription quantitative polymerase chain reaction (qRT-PCR) and lactate dehydrogenase enzymatic methods.
Results: Results showed that either Nisin at concentration of 20mg/ml or NaF at 1.2mg/ml inhibited the growth of S. mutans. Nisin revealed synergism with NaF with FIC indexes ≤ 0.5. NaF and Nisin can inhibit the acid production of S. mutans strongly. The effect is stronger when both are present. It was found that the combination of the two drags at sub-inhibitory concentrations had a significant inhibitory effect on the formation of biofilm. Moreover, mixed drugs produced a stronger bactericidal effect on S. mutans biofilm compared with any drugs alone by CLSM. In addition, Nisin decreased the expression of genes related to extracellular polysaccharide (EPS) synthesis (gtfB, gtfC, gtfD and spaP) and acidogenicity (ldh) , and the effect is more obvious under the action of NaF.
Conclusions: In conclusion, Nisin and NaF have a good synergistic effect against S. mutans and may be used as an effective drug combination for the prevention of dental caries.