Microbiological Impact of Chlorhexidine on Oral Biofilm Communities: Bacterial Ecology, Biofilm Disruption, and Antimicrobial Dynamics
DOI:
https://doi.org/10.22317/jcms.v12i4.2229Keywords:
Chlorhexidine, Oral microbiology, Biofilm, Oral microbiome, Antimicrobial activity, Dental plaqueAbstract
Objectives: The purpose of this study was to assess the microbiological effects of chlorhexidine on multispecies oral biofilm communities, specifically bacterial ecology, biofilm disruption, and antimicrobial dynamics
Methods: A multispecies biofilm model was created in vitro under clinically relevant conditions through the use of oral bacterial strains. Biofilms were exposed to chlorhexidine (0.02%, 0.06%, and 0.12%). Colony-forming unit (CFU) counting was used to determine the viability of bacteria, and crystal violet stain was used to quantify the biomass of biofilm. Conventional microbiological identification techniques were used to assess microbial composition. One-way ANOVA with the use of Tukey post hoc test was conducted.
Results: Chlorhexidine exhibited a strong concentration-related antimicrobial action on oral biofilm made of many species. Bacteria viability as well as biofilm biomass were significantly reduced in all treatment categories (p < 0.05). Microbial viability declined by a maximum of 85.5% at the highest concentration (0.12%) and the biofilm biomass declined by 78% which suggests that biofilm integrity was significantly disturbed. Also, it was found that not all bacterial species were equally susceptible with Gram-positive species being more susceptible to it than Gram-negative anaerobes. Nevertheless, this was followed by residual presence of bacteria in the biofilm matrix which implied protective mechanisms that reduce total elimination of antimicrobials.
Conclusion: Chlorhexidine has many effects on oral biofilm structure and bacterial viability that go beyond antimicrobial activity to other effects of inhibition of microbial ecology and selective pressure in biofilm communities. These results demonstrate that biofilm-level mechanisms need to be taken into account when considering the use of antiseptics in clinical dentistry.
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