[Seropositivity against atypical pneumonia agents demonstrated in patients with community-acquired pneumonia].

The aim of this study was to investigate the IgG and IgM antibody positivities against atypical pneumonia agents in patients with community-acquired pneumonia (CAP), and to compare the results with the controls. The serum samples which were collected from 53 adult patients and 20 healthy donors have been investigated by a commercial indirect immunofluorescent assay (IFA, Pneumo-slide, Vircell SL, Spain) in which nine different antigens were fixed onto a slide. In both of the study groups. IgG and IgM seropositivities were detected in different rates against one or more etiologic agents. In the patient group. IgG and IgM positivity rates for the agents were as follows, respectively; 22.6% and 28.3% for Legionella pneumophila, 9.4% and 5.6% for Mycoplasma pneumoniae, 30.1% and 7.5% for Coxiella burnetii, 33.9% and 3.7% for Chlamydia pneumoniae, 28.3% and 0 for adenovirus, 71.6% and 1.8% for respiratory syncytial virus, 30.1% and 24.5% for influenza A virus, 35.8% and 7.5% for influenza B virus, 71.6% and 1.8% for parainfluenza viruses type 1-3. The rates of IgG positivities in the control group varied between 5-55% for all of the agents except M. pneumoniae and 3 of these controls were positive for L. pneumophila IgM, 3 were positive for C. pneumoniae IgM and one was positive for influenza A virus IgM. According to the statistical evaluation, there were no significant differences for IgM seropositivities to any of the agents, between the patient and control groups (p > 0.05). These results could be attributed to one or more of the following; a) none of these microorganisms were the primary etiologic agents, b) IgM positivities were the result of reinfections with these agents, c) longer duration of IgM antibodies after the acute infections. In terms of IgG positivities between the patient and control groups, only C. burnetii showed statistically significant difference (p = 0.029). Since the type of the pathogens causing CAP are of crucial importance both for the epidemiological purposes and for planning the empirical treatment strategies, more detailed multicenter studies should be performed in our country.