A novel compound to maintain a healthy oral plaque ecology in vitro

摘要

Objective:DentalcariesiscausedbyprolongedepisodesoflowpHduetoacidproductionbyoralbiofilms.Bacteriawithinsuchbiofilmscommunicateviaquorumsensing(QS).QSregulatesseveralphenotypicbiofilmparameters,suchasbiofilmformationandtheproductionofvirulencefactors.Inthisstudy,weevaluatedtheeffectofseveralQSmodifiersongrowthandthecariogenicpotentialofmicrocosmoralbiofilms.Methods:Biofilmswereinoculatedwithpooledsalivaandculturedinthepresenceofsucrosefor48and96h.QSmodifiers(orcarriercontrols)werecontinuouslypresent.Lacticacidaccumulationcapacitieswerecomparedtoevaluatethecariogenicpotentialofthebiofilms.Subsequently,biofilmgrowthwasquantifiedbydeterminingcolonyformingunitcounts(CFUs)andtheirecologyby16SrDNA-basedmicrobiomeanalyses.Theminimalinhibitoryconcentration(MIC)forseveralStreptococcusspp.wasdeterminedusingmicrobrothdilution.Results:OfthetestedQSmodifiersonly3-oxo-N-(2-oxocyclohexyl)dodecanamide(3-Oxo-N)completelyabolishedlacticacidaccumulationbythebiofilmswithoutaffectingbiofilmgrowth.Thiscompoundwasselectedforfurtherinvestigation.Theactiverangeof3-Oxo-Nwas10–100μM.ThehomologousQSmolecule,acylhomoserinelactoneC12,didnotcounteractthereductioninlacticacidaccumulation,suggestingamechanismotherthanQSinhibition.MicrobialecologyanalysesshowedareductionintherelativeabundanceofStreptococcusspp.infavoroftherelativeabundanceofVeillonellaspp.inthe3-Oxo-Nexposedbiofilms.TheMICof3-Oxo-Nforseveralstreptococcalspeciesvariedbetween8and32μM.Conclusion:3-Oxo-Nchangestheecologicalhomeostasisofinvitrodentalplaque.Itreducesitscariogenicpotentialbyminimizinglacticacidaccumulation.Basedonourinvitrodata,3-Oxo-Nrepresentsapromisingcompoundinmaintainingahealthy,non-cariogenic,ecologyininvivodentalplaque.Keywords:Invitrobiofilms;caries;quorumsensing;healthyecology;3-oxo-N-(2-oxocyclohexyl)dodecanamide;dentalplaque(Published:29July2016)Citation:JournalofOralMicrobiology2016,8:32513-http://dx.doi.org/10.3402/jom.v8.32513