Mechanistic Insight into the Anti-Bacterial/Anti-Biofilm Effects of Low Chlorhexidine Concentrations on <i>Enterococcus faecalis</i>—In Vitro Study
Background: Endodontic treatment failures are often linked to the persistence of <i>Enterococcus faecalis</i> in the root canal system. This study aimed to investigate the antibacterial/antibiofilm mechanism of chlorhexidine (CHX), particularly at low concentrations, against <i>E....
Saved in:
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-11-01
|
| Series: | Microorganisms |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2076-2607/12/11/2297 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | Background: Endodontic treatment failures are often linked to the persistence of <i>Enterococcus faecalis</i> in the root canal system. This study aimed to investigate the antibacterial/antibiofilm mechanism of chlorhexidine (CHX), particularly at low concentrations, against <i>E. faecalis</i>, to improve endodontic treatment protocols. Methods: The antibacterial activity of CHX (0.125–20 μg/mL) was evaluated against <i>E. faecalis</i> ATCC 29212 using various assays, including planktonic growth inhibition, colony-forming units (CFUs), membrane permeability and potential assays, high-resolution scanning electron microscopy (HR-SEM), confocal laser scanning microscopy of biofilms, biomass and metabolic activity assays on matured biofilm, and quantitative real-time PCR for gene expression. Statistical analysis was performed using Student’s <i>t</i>-test and ANOVA. Results: CHX demonstrated concentration-dependent inhibition of <i>E. faecalis</i>, significantly reducing planktonic growth and CFUs. Membrane assays showed increased permeability and depolarization, indicating damage. HR-SEM revealed morphological changes, such as pore formation, while confocal microscopy showed a reduction in biofilm mass and extracellular substances. Gene expression analysis indicated the downregulation of virulence genes and upregulation of stress response genes. Conclusions: CHX at low concentrations disrupts <i>E. faecalis</i> at multiple levels, from membrane disruption to gene expression modulation, affecting mature biofilm. These findings support the refinement of endodontic disinfection protocols to reduce microbial persistence. |
|---|---|
| ISSN: | 2076-2607 |