Susceptibilities of Actinobacillus actinomycetemcomitans biofilms to oral antiseptics.

The susceptibilities of Actinobacillus actinomycetemcomitans cultures, grown as 1- or 3-day-old biofilms or as planktonic suspensions, to concentrations of chlorhexidine digluconate, cetylpyridinium chloride or triclosan used in commercial mouthwashes were compared. Three-day biofilms were the most resistant form of the organism and chlorhexidine was the most active antiseptic. Comparison of solutions of the pure antibacterial agent with commercial products containing the same concentration of antiseptic showed little difference in in-vitro activities. The results emphasise that the testing of antimicrobial mouthwashes should be performed on bacteria grown as biofilms.