Evaluation of different techniques used for diagnosis of chlamydia pneumoniae infection

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. Many studies were undertaken to assess whether polymerase chain reaction [PCR] could be a useful addition to the serological techniques routinely practiced for diagnosis. This study investigated 100 patients with a diagnosis of acute respiratory tract infection. Nasopharyngeal swab [NPS] obtained from these 100 patients were evaluated by PCR- enzyme immunoassay [PCR - EIA] for the presence of C pneumoniae DNA and by direct immunofluorescence [DIF] and staining by Giemsa stain for detection of its antigens. Serological determination of IgG antibodies against C. pneumoniae were performed by means of an enzyme linked immunosorbant assay [rELISA]. Seventeen patients [17 percent] were positive by both PCR and rELISA, while 5 patients [5 percent] were positive by rELISA and negative by PCR. By using DIP test, 13 patients [13 percent] were positive. There were 8 patients [8 percent] positive by Giemsa staining. Better definition of the serological criteria and improved performance of the PCR technique, are necessary to confirm the etiological role of C. pneumoniae in acute and chronic respiratory infections