No evidence of involvement of Chlamydia pneumoniae in severe cerebrovascular atherosclerosis by means of quantitative real-time polymerase chain reaction.
OBJECTIVE
All studies reporting high numbers of Chlamydia pneumoniae DNA positives in stroke patients published to date have used polymerase chain reaction (PCR) techniques highly prone to generate false-positive results. The aim of this study was to analyze the prevalence of C. pneumoniae DNA in plaques of the carotid artery as well as in peripheral blood by means of a new, closed, real-time PCR system.


METHODS
Carotid endarterectomy specimens and preoperative peripheral blood mononuclear cells (PBMC) of 75 individuals with severe cerebrovascular atherosclerosis were analyzed by means of a C. pneumoniae-specific quantitative ompA-based real-time PCR TaqMan system. Plaques were also cultured onto HEp-2 cells. Before the surgical intervention, C. pneumoniae-specific IgM, IgG, and IgA as well as C-reactive protein (CRP) levels were determined.


RESULTS
89% of all patients studied had C. pneumoniae-specific antibodies, but the pathogen was not detected in a single carotid atheroma by real-time PCR and cell culture. However, C. pneumoniae DNA was detected in 4 PBMC samples (5.3%) at very low levels (<1 inclusion/6 mL EDTA blood). No statistical significance was found between symptomatic/asymptomatic patients, C. pneumoniae PCR, results and CRP values after correction for multiplicity-of-test adjustment.


CONCLUSIONS
By means of a closed, highly sensitive, and specific real-time PCR, C. pneumoniae was not detected in cerebrovascular atherosclerosis. PCR on PBMC was not predictive for endovascular chlamydia infection and most likely stem from previous C. pneumoniae respiratory tract infection in individual cases.
Apfalter
Petra
P
Department of Clinical Microbiology, Institute of Hygiene and Medical Microbiology, University of Vienna, National Reference Laboratory for Chlamydia pneumoniae, Vienna University Hospital, Austria. petra.apfalter@meduniwien.ac.at
Barousch
Wolfgang
W
Nehr
Marion
M
Willinger
Birgit
B
Rotter
Manfred
M
Hirschl
Alexander M
AM
D000368:Aged; D000907:Antibodies, Bacterial / Q000097:blood; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D002340:Carotid Artery Diseases / Q000097:blood / Q000382:microbiology* / Q000601:surgery; D023521:Chlamydophila Infections / Q000453:epidemiology* / Q000276:immunology; D016993:Chlamydophila pneumoniae / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification / Q000472:pathogenicity*; D003199:Computer Systems; D004269:DNA, Bacterial / Q000302:isolation & purification*; D004691:Endarterectomy; D005260:Female; D006801:Humans; D002537:Intracranial Arteriosclerosis / Q000382:microbiology*; D007963:Leukocytes, Mononuclear / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D015995:Prevalence
D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; D004269:DNA, Bacterial; C078167:OMPA outer membrane proteins