A Comparative Analysis of the Antimicrobial Efficacy of Nisin in Different Vehicles Against Enterococcus faecalis: An In Vitro Study

Aim To evaluate and compare the antimicrobial efficacy of nisin in different carriers against <i>Enterococcus faecalis</i>. Materials and methods Test materials were divided into four groups of five samples each as follows: group 1 = nisin + 17% ethylenediaminetetraacetic acid (EDTA); group 2 = nisin + 2% chitosan; group 3 = nisin + 2% chlorhexidine; group 4 = nisin + distilled water (control). The antimicrobial effectiveness was assessed using the direct contact method, where a standardized <i>E. faecalis</i> suspension was applied to the test materials. Optical density (OD) was assessed using enzyme-linked immunosorbent assay (ELISA) at the end of days one and seven. Data were analyzed using ANOVA and Tukey's post hoc analysis. The level of significance was set at p < 0.05. Results On day one, there was a significant difference in the mean OD values (p < 0.001) with group 3 showing the highest, followed by groups 1, 2, and 4. On day seven, all groups demonstrated antibacterial activity (group 1 > group 3 > group 4 > group 2) but the differences were not statistically significant (p = 0.393). Intragroup analysis showed a decrease in the OD values from day one to day seven, the difference of which was not significant in all groups except group 1, which showed a significant difference (p = 0.035). Conclusion The antibacterial efficacy of nisin was synergistically enhanced with the addition of 17% EDTA and 2% chlorhexidine over seven days against <i>E. faecalis</i>.