Medical Microbiology

Chlamydia 335

Diagnosis.Specialstainingtechniquesareusedtorenderbartonellaevisible

underthemicroscopeintissuespecimens.Growthinculturesmorethan

sevendays.AmplificationofspecificDNAintissuesamplesorblood,followed

bysequencing.AntibodyassaywithIForEIA.

Therapy.Tetracyclines,macrolides.

Epidemiologyandprevention.Oroyafever(alsoknownasCarriondisease)is

observedonlyinhumansandisrestrictedtomountainvalleyswitheleva-

tionsabove 800 minthewesternandcentralCordillerasinSouthAmerica

becauseanessentialvector,thesandfly,livesonlythere.Catscratchdisease,

ontheotherhand,isknownallovertheworld.Itistransmitteddirectlyfrom

catstohumansorindirectlybycatfleas.Thecatsinvolvedareusuallynotsick.

Table4. 14 liststhepathogensandclinicalpicturesforthevariousbartonel-

loses.

Afipiafelis

ThebacterialspeciesAfipia(ArmedForcesInstituteofPathology)feliswas

discoveredseveralyearsago.Atfirst,itappearedthatmostcasesofcat

scratchdiseasewerecausedbythispathogen.Thenitturnedoutthatthe

culpritinthosecaseswasusuallyeitherB.henselaeorB.clarridgeiaand

thatAfipiafeliswasresponsibleforonlyasmallnumber.Afipiafelisand

B.henselaecatscratchinfectionspresentwiththesameclinicalsymptoms.

MostcasesofA.felisinfectionsclearupspontaneouslywithoutantibiotic

therapy.Shoulduseofanantibioticbeclinicallyindicated,atetracycline

(orinseverecasesacarbapenemoraminoglycoside)wouldbeappropriate.

Chlamydia

&Chlamydiaeareobligatecellparasites.Theygothroughtwostagesintheir

reproductivecycle:theelementarybodies(EB)areoptimizedtosurviveout-

sideofhostcells.Intheformoftheinitialbodies(IB),thechlamydiaerepro-

duceinsidethehostcells.Thethreehumanpathogenspeciesofchlamydiae

areC.psittaci,C.trachomatis,andC.pneumoniae.Tetracyclinesandmacro-

lidesaresuitablefortreatmentofallchlamydialinfections.

C.psittaciisthecauseofpsittacosisorornithosis.Thiszoonosisisasys-

temicdiseaseofbirds.Thepathogensenterhumanlungswhendustcontain-

ingchlamydiaeisinhaled.Afteranincubationperiodofonetothreeweeks,

pneumoniadevelopsthatoftenshowsanatypicalclinicalcourse.

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Kayser, Medical Microbiology © 2005 Thieme