Frequency of detection of Chlamydophila pneumoniae using bronchoalveolar lavage fluid in patients with community-onset pneumonia.

BACKGROUND: Chlamydophila pneumoniae is a causative pathogen of lower respiratory tract infection, which generally infects healthy, young people. However, it is often difficult to evaluate acute C. pneumoniae infection using upper respiratory tract specimens and/or sputum samples due to its persistent infection or colonization. The interpretation of frequency of detection of C. pneumoniae seems to be insufficient in community-onset pneumonia. The aim of this study was to evaluate the presence of C. pneumoniae using bronchoalveolar lavage fluid (BALF) samples.

METHODS: BALF samples from 147 patients with pneumonia were retrospectively evaluated using C. pneumoniae-specific polymerase chain reaction (PCR) primers.

RESULTS: None of the samples had positive PCR results for C. pneumoniae using two different sets of specific primers. Single and paired serological analyses were performed in 54 (36.7%) and 37 (25.2%) patients, respectively. These analyses revealed that 1 of 37 (2.7%) patients had a presumptive acute infection with C. pneumoniae, 8 of the 54 (14.8%) patients were suspected of having a C. pneumoniae infection, and 7 of the 37 (18.9%) patients were suspected of having past C. pneumoniae infection. In addition, cultivation and/or 16S rRNA gene sequencing detected Haemophilus influenzae in the presumptive case using the serological method.

CONCLUSIONS: The results of the present study revealed that C. pneumoniae might be a minor causative agent of community-onset pneumonia according to an evaluation of specimens obtained from the lower respiratory tract.