Effect of Sub Minimal Inhibitory Concentration Cetylpyridinium Chloride on Biofilm Formation and Hydropyobicity of Streptococci and Actinomycetes

Background and Objectives: If the antimicrobial agent is not administered continuously, the concentration of the antimicrobial agent necessarily becomes lower than the minimum inhibitory concentration (MIC) and maintains the sub- minimum inhibitory concentration (sub-MIC). There were no studies on the biofilm formation of initial attachment bacteria such as streptococci and actinomyces in cetylpyridinium chloride. In this study, we investigated the effect of cetylpyridinium chloride of sub-MIC on biofilm formation and bacterial cell hydrophobicity using Streptococcus mutans, Streptococcus gordonii, Actinomyces naeslundii and Actinomyces odontolyticus.

Materials and Methods: The degree of biofilm formation was classified into 1-4 according to the degree of adhesion to glass slip. Hydrophobicity was measured to investigate whether differences in biofilm formation were related to differences in bacterial surface hydrophobicity.

Results: When biofilm formation was compared between the control group without cetylpyridinium chloride and the cetylpyridinium chloride sub-MIC, biofilm formation was decreased in the experimental group of S. mutans and A. naeslundii. Cellular hydrophobicity was observed with regard to adhesion and the hydrophobicity of S. mutans and A. naeslundii decreased in the experimental group compared to the control group. However, S. gordonii did not change biofilm formation, but cell hydrophobicity was significantly increased in the experimental group compared to the control group.

Conclusion: When cetylpyridinium chloride was applied to oral bacteria, there was a correlation between biofilm formation and cell hydrophobicity in some bacteria.