Comparison of two serological methods and a polymerase chain reaction- enzyme immunoassay for the diagnosis of acute respiratory infections with Chlamydia pneumoniae in adults.

Petitjean J,      Vincent F,      Fretigny M,      Vabret A,      Poveda JD,      Brun J,      Freymuth F     

Chlamydia pneumoniae
Chlamydia Infections
Respiratory Tract Infections
Acute Disease
Adult
Aged
Aged, 80 and over
Antibodies, Bacterial
Asthma
Bronchi
Bronchoalveolar Lavage Fluid
Community-Acquired Infections
Comparative Study

DNA, Bacterial
Enzyme-Linked Immunosorbent Assay
Female
Fluorescent Antibody Technique, Direct
Human
Immunoenzyme Techniques
Male
Middle Age
Nasopharynx
Pneumonia, Bacterial
Polymerase Chain Reaction
Prospective Studies
Sensitivity and Specificity

Abstract
Chlamydia pneumoniae is a common respiratory tract pathogen.  Serological methods currently used for the diagnosis of C. pneumoniae infection lack specificity, give ambiguous results from a single serum sample and often provide only a retrospective diagnosis.  A prospective study was undertaken to assess whether PCR could be a useful addition to the serological techniques routinely practised for diagnosis.  This study investigated 68 adult patients with a diagnosis of acute respiratory infection.  Acute and convalescent serological determination of antibodies to C. pneumoniae were performed by means of an rELISA test and a micro-immunofluorescence (MIF) test.  Nasopharyngeal aspirates or bronchoalveolar lavage specimens and bronchial aspirates obtained from the 68 patients were evaluated by PCR-enzyme immunoassay (PCR-EIA) for the presence of C. pneumoniae and by immunofluorescence assay and cell culture for virus identification.  Mycoplasma pneumoniae serology was also performed.  Eight patients (11.8%) were positive by either rELISA or PCR-EIA, or both, with an infection rate of 5 (18.5%) of 27 in patients with community-acquired pneumonia, 2 (9%) of 22 in asthmatic patients and 1 (5%) of 19 in patients with an exacerbation of chronic obstructive pulmonary disease.  Serological evidence of acute infection was found in four of these patients with the rELISA test and in three others with the MIF test.  PCR-EIA detected C. pneumoniae DNA in four specimens, but there were concordant results with both rELISA and PCR- EIA in only one patient A positive PCR-EIA was also obtained in a patient who did not show an antibody response in acute serum.  The discrepancy between serological and PCR-EIA results reflects the difficulties in routine laboratory diagnosis of C. pneumoniae infection and the necessity for further studies with optimised techniques.

Laboratory of Human and Molecular Virology
CHRU Caen
France.