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

## TL;DR

This study compares how well nisin mixed with different substances fights Enterococcus faecalis bacteria in a lab setting.

## Contribution

The study identifies that nisin's antimicrobial effect is enhanced when combined with EDTA or chlorhexidine.

## Key findings

- Nisin with chlorhexidine showed the highest antimicrobial activity on day one.
- Nisin with EDTA maintained significant antibacterial activity over seven days.
- Combining nisin with EDTA or chlorhexidine enhanced its antibacterial efficacy against E. faecalis.

## Abstract

Aim

To evaluate and compare the antimicrobial efficacy of nisin in different carriers against Enterococcus faecalis.

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 E. faecalis 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 E. faecalis.