•  Vaginal bacterial communi0es are thought create and maintain a lowenvironmental pH that restricts the growth of non‐indigenouspopula0ons.

•  We sought to assess the stability of vaginal bacterial communi0es andmodeltemporaldynamics.

•  33 asymptoma0c, reproduc0ve‐age women self‐collected mid‐vaginalswabs every third day for 16 weeks as part of a vaginal douchingcessa0onstudy.(Brotmanetal.AmJObstetGynecol2008)

•  Bacterial community composi0on was determined based on 16S rRNAgenesequences(V1‐V2region).

•  A dataset of more than 2.97 million 16S rRNA gene sequences wasobtainedfrom988samples(29.9±1.6(SD)samplespersubject)withanaverage of 3,005 ± 1257 (SD) sequences per sample. Taxonomicassignmentswere performed as described by Ravel et al. (PNAS 2010)usingacombina0onoftheRDPclassifierandSpeciateIT.

•  A linearmixed effectmodel for the log of Jensen‐Shannon divergencerate of community change was used to inves0gate the role ofmenstrua0on and sexual ac0vity on the constancy of the vaginalmicrobiota.Themodelaccountedforcorrela0onsbetweensamplesfromthe same par0cipant and was adjusted for 0me‐varying confoundersincluding vaginal douching, contracep0ve and normalized menstrualcycle0me.

•  COMMUNITYSTATETYPE:Astatetypeiscomprisedofsamplesthathavesimilarbacterialspeciescomposi0on.Inthisstudyfivecommunitystatetypes were iden0fied. Profiles of community state types weredeterminedforeachwoman.

•  COMMUNITYSTATECLASS:Acommunitystateclassisformedofsimilarcommunitystateprofiles.

•  Thespeciescomposi+onofbacterialcommuni+esinsomewomenchangedmarkedlyovershortperiodsof+mewhileinothersitwasrela+velystable.

•  Modelingofvaginalbacterialcommunitydynamicsindicatesthatcommunitystabilitywasassociatedwith+meinthemenstrualcycle,andvariedamongcommuni+esthatdifferedincomposi+on.

•  Abe?erunderstandingoffactorsthatleadtothedevelopmentandmaintenanceofspecificandstablevaginalcommuni+esisneededsostrategiescanbedevelopedtopromoteandmaintainreproduc+vehealth.

•  Infutureworkwewilldetermineifhabitsandprac+ces(includinguseoflubricants,feminine hygiene products, and specific sexual behaviors) influence communitydynamics.

1DepartmentofBiologicalSciences,UniversityofIdaho,Moscow,Idaho,USA,2Ini+a+veforBioinforma+csandEvolu+onaryStudies(IBEST),UniversityofIdaho,Moscow,Idaho,USA,3DepartmentofEpidemiologyandPublicHealth,UniversityofMarylandSchoolofMedicine,Bal+more,Maryland,USA,4Ins+tuteforGenomeSciences,UniversityofMarylandSchoolofMedicine,Bal+more,Maryland,USA,5DepartmentofMathema+cs,UniversityofIdaho,

Moscow,ID,USA,6DepartmentofSta+s+cs,UniversityofIdaho,Moscow,ID,USA,7DepartmentofMicrobiologyandImmunology,UniversityofMarylandSchoolofMedicine,Bal+more,Maryland,USA

RoxanaJ.Hickey1,2,RebeccaM.Brotman3,4,PawelGajer4,JoyceSakamoto4,SaraS.K.Koenig4,LiFu4,XiaZhou1,2,ZaidAbdo2,5,6,JacquesRavel4,7,LarryJ.Forney1,2

Temporal dynamics of vaginal bacterial communities

Figure1. Heatmapofphylotyperela0ve abundance from all 998samples longitudinally collectedfrom 33 women. Each ver0callinerepresentsonesample.

Three of the community state typeswere dominated by Lactobacillus sp.andrepresented17%(communitystatetype I), 6% (community state type II)and 41% (community state type III) ofthe samples. A total of 36% of thesamples did not contain significantnumber of Lactobacillus species(communitystatetypeIV‐AandIV‐B).

Figure 2. Dynamics of vaginalcommunity state types in 33womenover16weeks.

A.  Dendrogram of distancesbetweenpropor+onsof thefivecommunity state within awomanover+me.

B.  Heatmap of propor+ons ofcommunity state typesmeasuredwithin awoman over+me.

C.  Color bar indica+ng communityclass (DA, LC, LG,DB, and LI) asdefined by clusters ofpropor+ons of community statetypeswithinawomanover+me.

D.  Temporal profiles of communitystate types for 33 women over16 weeks. Each +me point isrepresented by a color‐codedcommunity state type assignedtothecorrespondingcommunitystate.

E.  Box plot of Nugent scores foreachwomanover16weeks.

Figure3.Vaginalcommunitydynamics.

Panels(A)and(C).Subject21and2‐Interpolatedbargraphsofphylotypesabundance.Metadataandprofileofcommunitystatestypesareshownbelow.

Panels(B)and(D).Schema+csofthedynamicsofvaginalcommuni+esofsubject21and2inthevaginalcommunityspaceasdefinedbyRaveletal.(PNAS2010).

Figure 4. Examples of vaginalbacterial community that exhibitlowdynamics.

Communitydynamicsarerepresentedbyaheatmap(top)andaninterpolatedbargraphofphylotypesabundance(middle).The bo?om panel shows the rate ofchange of the Jensen‐Shannondivergence, and selected metadata,includingmensesandsexualac+vi+es.

Figure5.Examplesofvaginalbacterialcommunitythatexhibithighdynamics.(SeelegendFig.4)

ThisworkwassupportedbygrantsUH2AI083264andK01AI080974fromtheNa+onalIns+tuteofAllergyandInfec+ousDiseases,Na+onalIns+tutesofHealth.

•  Itisthemostcommonmemberofvaginalcommuni+esamongwomenofallethnicgroups.

•  L. iners has the smallest genome (~1.3Mb) of all known Lactobacillus sp.;appears to have undergone dras+cgenomereduc+on(Macklaimetal.PNAS2010). The genomes of other vaginalLactobacillus sp. range from ~1.6 – 2.3Mb.

•  Genomic featuresofL. iners: incompleteTCA cycle; missing genes include thoserequired for synthesis of vitamins,cofactors,aminoacidsandpurines.

•  IsL.inersdependentontheirneighborsforgrowthandsurvival–isthereanecologicalnetworkbasedonnutri+onal dependencies?Whatdisrupts thesecommunitynetworks?

•  Aredifferencesincommunitycomposi+onrelevanttodifferencesincommunitystability?

WhyisL.inersofinterest? Communitynetworks,ecologicalresistanceandresilience

Walker’s“Driver‐PassengerModel”•  One or more species “drive” the community; the

remainder are not essen+al for communityperformanceandmayvary.

•  We postulate that lac+c acid bacteria drive thevaginalecosystem

L.iners

Species1

Species2

Species3

Species4

Species5

?

RESEARCHAIMS1.  Gain a be?er understanding of the strain

diversity of L. iners in the vagina. Are theredifferences in the metabolic capabili+es orecologicalfunc+onsofstrains?

2.  Iden+fy and characterize ecological networksof bacteria that L. iners may depend on forsurvivalandpersistence.

FrequencyorDura0on

DisturbedEcosystem

Intensity