A combination of cis-2-decenoic acid and chlorhexidine removes dental plaque.
OBJECTIVE
To investigate the ability of cis-2-decenoic acid (C2DA) to induce dispersion in single-species biofilms formed by Streptococcus mutans and Candida albicans, as well as to remove their bacterial-fungal dual-species biofilms when combined with low concentrations of chlorhexidine (CHX).


METHODS
For biofilm dispersal bioassays, single-species biofilms of S. mutans and C. albicans were grown on the inside surface of petri dishes, using a semi-batch culture method in which the medium was replaced every 24h for 5 days. Biofilms were then treated with very low concentrations of C2DA (100 and 310 nM) for 1h to release cells into the bulk liquid and to evaluate dispersed cell number by measuring the optical density (OD). To assess the ability of C2DA combined CHX treatments to remove tested microorganisms' dual-species biofilms, they were grown on saliva-coated hydroxyapatite (sHA) discs for 48 h and then were treated with three different concentrations of CHX (0.08%, 0.06% and 0.04%) alone or in combination with indicated concentrations of C2DA for 1 min twice daily for 3 subsequent days. Biofilms were then either subjected to the field emission scanning electron microscopy (FESEM) analysis or harvested and colony forming units (CFUs) were counted after plating on agar.


RESULTS
Treatment of pre-established biofilms with 310 nM C2DA caused an approximately two-fold increase in the number of planktonic cells in both cultures. A combination of 310 nM C2DA and 0.04% CHX resulted in significant removal (p-value <0.05) of dual-species biofilms from sHA discs surface.


CONCLUSIONS
Anti-biofilm characteristic of C2DA boosts the action of CHX even at low concentrations.
Department of Biology, Alzahra University, Tehran, Iran. Electronic address: a.rahmanibadi@gmail.com.
Azadeh
A
Rahmani-Badi
Department of Biology, Alzahra University, Tehran, Iran. Electronic address: shayestehsepehr@gmail.com.
Shayesteh
S
Sepehr
Department of Biology, Alzahra University, Tehran, Iran. Electronic address: hamtababaie@yahoo.com.
Hamta
H
Babaie-Naiej
D018441:Biofilms / Q000187:drug effects*; D002176:Candida albicans / Q000187:drug effects* / Q000502:physiology; D002710:Chlorhexidine / Q000494:pharmacology*; D003773:Dental Plaque / Q000188:drug therapy*; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D005229:Fatty Acids, Monounsaturated / Q000494:pharmacology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D008855:Microscopy, Electron, Scanning; D012463:Saliva / Q000737:chemistry; D013295:Streptococcus mutans / Q000187:drug effects* / Q000502:physiology
D005229:Fatty Acids, Monounsaturated; C052476:2-decenoic acid; D002710:Chlorhexidine
Candida albicans; Chlorhexidine; Dual-species biofilms; Streptococcus mutans; cis-2-Decenoic acid