SkiptomaincontentChlamydiapneumoniaeisfrequentlydetectedinthebloodafteracutelunginfectionL.Witte,D.Droemann,K.Dalhoff,J.RuppEuropeanRespiratoryJournal201137:712-714;DOI:10.1183/09031936.00102310L.WitteFindthisauthoronGoogleScholarFindthisauthoronPubMedSearchforthisauthoronthissiteD.DroemannFindthisauthoronGoogleScholarFindthisauthoronPubMedSearchforthisauthoronthissiteK.DalhoffFindthisauthoronGoogleScholarFindthisauthoronPubMedSearchforthisauthoronthissiteJ.RuppFindthisauthoronGoogleScholarFindthisauthoronPubMedSearchforthisauthoronthissiteForcorrespondence:[email protected]&DataInfo&MetricsPDFTotheEditors:TheobligateintracellularbacteriumChlamydiapneumoniaeisacommoncauseofacuterespiratoryinfectionswithaworldwideseroprevalenceofupto70%1.Bacterialpersistencefollowingacuteinfectionintherespiratorytractorinatheroscleroticbloodvesselshasbeensuggestedtobeinvolvedinthepathogenesisofchronicinflammatorydiseases,suchaschronicobstructivepulmonarydiseaseandatherosclerosis2,3.IthasbeenshowninanimalmodelsthatafteracutelunginfectionwithC.pneumoniae,thepathogenissystemicallydistributedinthebloodcirculationusingbloodmonocytesasavector4,5.However,datasupportingthishypothesisinhumansarestillmissing.Frominvitroobservations,itisknownthatC.pneumoniaeinfectionofhumanbloodmonocytesresultsinanonreplicativebutviablestateofthepathogen,whichisrefractorytoantibiotictreatment6.TheobjectiveofthisstudywastoanalysewhetherC.pneumoniaesystemicallydisseminatesfromthelungtothebloodinpatientswithanacutelowerrespiratorytractinfection(LRTI).PatientsrecoveringfromacuteC.pneumoniaelunginfectionweremonitoredforthepresenceofC.pneumoniaeDNAinthebloodduringfollow-upvisits(at30and90dayspostinfection)andcomparedwithpatientsafterStreptococcuspneumoniaeinfection.PatientspresentingattheemergencyroomoroutpatientdepartmentsoftheUniversityHospitalSchleswig-Holstein,CampusLuebeck(Luebeck,Germany)withradiographicallyconfirmednonseverecommunity-acquiredpneumonia(CAP)orsevereLRTIwithfever,productivecoughandp