Recovery of Oral in Vitro Biofilms after Exposure to Peptides and Chlorhexidine.

ABSTRACT Introduction This study aimed to examine the dynamic recovery of established multispecies biofilms of oral bacteria after an initial treatment by D-enantiomeric peptide DJK-5, L-enantiomeric peptide 1018 or chlorhexidine digluconate (CHX). Methods Oral biofilms from two donors were grown on collagen-coated hydroxyapatite disks for three weeks and exposed to DJK-5, 1018 and 2% CHX for 3 min. Immediately after treatment and 1, 2, 3, 5, 7, 8 and 12 weeks after exposure, the biofilm volume and the volume ratio of dead and live bacteria in biofilms was assessed by confocal laser scanning microscopy by using a LIVE/DEAD viability stain. Results were examined by one-way ANOVA and post hoc multiple comparisons to determine significance at the p Results DJK-5 killed almost 80% of biofilms in 3 min and maintained this high level of dead bacteria for one week. The proportion of viable bacteria in DJK-5 treated biofilms returned to the pre-treatment level after twelve weeks. The biovolume of DJK-5 treated biofilm remained significantly lower than that of biofilms after CHX and no treatment throughout the 12-week follow-up period (p Conclusions Recovery time after exposure to DJK-5 was longer than that after exposure to 1018 and CHX. Peptide 1018 showed a delayed, continued antibacterial effect similar to that of 2% CHX against the biofilm microbes.