Int J Oral Biol.  2016 Dec;41(4):209-215. 10.11620/IJOB.2016.41.4.209.

Effect of Sub-minimal Inhibitory Concentration of Chlorhexidine on Biofilm Formation and Coaggregation of Early Colonizers, Streptococci and Actinomycetes

• Lee SY
• Lee SY

• KMID: 2368584
• DOI: http://doi.org/10.11620/IJOB.2016.41.4.209

Abstract

Chlorhexidine has long been used in mouth washes for the control of dental caries, gingivitis and dental plaque. Minimal inhibitory concentration (MIC) is the lowest concentration of an antimicrobial substance to inhibit the growth of bacteria. Concentrations lower than the MIC are called sub minimal inhibitory concentrations (sub-MICs). Many studies have reported that sub-MICs of antimicrobial substances can affect the virulence of bacteria. The aim of this study was to investigate the effect of sub-MIC chlorhexidine on biofilm formation and coaggregation of oral early colonizers, such as Streptococcus gordonii, Actinomyces naeslundii and Actinomyces odontolyticus. The biofilm formation of S. gordonii, A. naeslundii and A. odontolyticus was not affected by sub-MIC chlorhexidine. However, the biofilm formation of S. mutans increased after incubation with sub-MIC chlorhexidine. In addition, cell surface hydrophobicity of S. mutans treated with sub-MIC of chlorhexidine, decreased when compared with the group not treated with chlorhexidine. However, significant differences were seen with other bacteria. Coaggregation of A. naeslundii with A. odontolyticus reduced by sub-MIC chlorhexidine, whereas the coaggreagation of A. naeslundii with S. gordonii remained unaffected. These results indicate that sub-MIC chlorhexidine could influence the binding properties, such as biofilm formation, hydrophobicity and coaggregation, in early colonizing streptococci and actinomycetes.

Keyword

chlorhexidine; biofilm; oral bacteria; hydrophobicity; coaggregation; sub-MIC

MeSH Terms

Actinobacteria*
Actinomyces
Bacteria
Biofilms*
Chlorhexidine*
Colon*
Dental Caries
Dental Plaque
Gingivitis
Hydrophobic and Hydrophilic Interactions
Mouth
Streptococcus gordonii
Virulence
Chlorhexidine