Medical Microbiology

324 4 BacteriaasHumanPathogens

foryears.Diagnosisisconfirmedbyidentificationoftreponemesfromthe

skinlesions.PenicillinGisusedintherapy.

Borrelia(RelapsingFever,LymeDisease)

&Borreliarecurrentisisthepathogenofanepidemicrelapsingfevertrans-

mittedbybodylicethatnolongeroccursinthepopulationofdeveloped

countries.B.duttonii,B.hermsii,andotherborreliaearethecausativepatho-

gensoftheendemic,tickbornerelapsingfever,socalledfortheperiodicre-

lapsesoffevercharacterizingtheinfection.Therelapsesarecausedbybor-

reliaethathavechangedthestructureofthevariablemajorproteinintheir

outermembranessothattheantibodiesproducedbythehostintheprevious

episodearenolongereffectiveagainstthem.Laboratorydiagnosticconfirma-

tionrequiresidentificationoftheborreliaeintheblood.PenicillinGisthe

antibioticofchoice.

B.burgdorferiisthecausativepathogeninLymedisease,atickbornein-

fection.Leftuntreated,thediseasehasthreestages.Theprimaryclinical

symptomofstageIistheerythemachronicummigrans.StageIIintheEuro-

peanvarietyisclinicallydefinedbychroniclymphocyticmeningitisBann-

warth.Meningitisisfrequentinchildren.Theprimarysymptomsofstage

IIIareacrodermatitischronicaatrophicansHerxheimerandLymearthritis.

Laboratorydiagnosticscomprisesdetectionofspecificantibodiesbymeans

ofimmunofluorescentorEIAmethods.Betalactamantibioticsareusedto

treattheinfection.Lymediseaseisthemostfrequenttickbornediseasein

centralEurope. &

BorreliathatCauseRelapsingFevers

Taxonomyandsignificance.ThegenusBorreliabelongstothefamilySpir-

ochaetaceae.Thebodylouseborneepidemicformofrelapsingfeveriscaused

bythespeciesB.recurrentis.Theendemicform,transmittedbyvarioustick

species,canbecausedbyanyofanumberofspecies(atleast 1 5),themost

importantbeingB.duttoniiandB.hermsii.

Morphologyandculture.Borreliaearehighlymotilespirocheteswiththree

toeightwindings,0.3–0.6lmwide,and 8 – 18 lminlength.Theypropel

themselvesforwardbyrotatingabouttheirlengthwiseaxis.Theycanberen-

deredvisiblewithGiemsastain(Fig.4. 24 ).Itispossibletoobservelivebor-

reliaeusingdarkfieldorphasecontrastmicroscopy.

4

Kayser, Medical Microbiology © 2005 Thieme