Application of serology and nested polymerase chain reaction for identifying Chlamydophila pneumoniae in community-acquired lower respiratory tract infections in children.

Context: Chlamydophila pneumoniae is a common cause of community-acquired respiratory infections, including pneumonia, bronchitis, and upper respiratory tract infections. Since it is difficult to detect C. pneumoniae in clinical practice, specific etiological diagnosis is established only in a minority of cases. Aims: To investigate the role of C. pneumoniae in community-acquired lower respiratory tract infections (LRTIs) in children, with the use of serological tests and nested polymerase chain reaction (PCR) analysis. Settings and Design: One hundred children, age of 2 months to 12 years, hospitalized for community-acquired LRTIs were investigated for C. pneumoniae etiology. Materials and Methods: We investigated 100 children hospitalized for community-acquired LRTIs, using enzyme-linked immunosorbent assay for detecting anti- C. pneumoniae immunoglobulin M, and immunoglobulin G antibodies and nasopharyngeal aspirates for analysis of C. pneumoniae PCR. The demographic, clinical, and radiological findings for C. pneumoniae antibody positive and C. pneumoniae antibody negative cases were compared. Statistical Analysis Used: Data analysis was performed by Chi-square test and Fisher's exact tests using Epi Info (2002). Results: Clinical and radiological findings in both the groups were comparable. A relatively higher rate of C. pneumoniae infection in children was observed below 5 years of age. Serological evidence of C. pneumoniae infection was observed in 12 (12%) patients and nested PCR was positive in 5 (5%) children. Thirteen (13%) patients were diagnosed with C. pneumoniae infection by serology and/or nested PCR. Conclusions: Our study confirms that C. pneumoniae plays a significant role in community-acquired LRTIs in children of all ages, even in children aged <5 years.