Abstract
Background: We reported the utility of multiplex real-time polymerase chain reaction (MRT-PCR) to diagnose pathogens causing community-acquired pneumonia (CAP) in Japanese adults at ERS 2013. The number of samples was limited, so we extended the study to Jan 2014. Aims: To confirm usefulness of MRT-PCR in diagnosing causative pathogens in a large number of adult Japanese CAP patients as compared with conventional tests (sputum/blood culture, urine antigen for Streptococcus pneumoniae [S.p]/Legionella pneumophila [L.p], and paired serum of Mycoplasma pneumoniae [M.p] antibody) Methods: We prospectively enrolled adult CAP patients from Sep 2012 to Jan 2014. CAP was defined based on respiratory symptoms and laboratory/chest X-ray findings excluding noninfectious causes.We collected sputum, nasopharyngeal swab, urine, and blood samples of each patient. MRT-PCR can identify 6 bacteria and 11 viruses in sputum and nasopharyngeal swab samples. Causative pathogens were identified by each test. Results: We analyzed 92 patients (mean age, 60 years; 53 men). Sensitivity of MRT-PCR was significantly higher than that of conventional tests in all cases (78% vs. 56%; p<0.01). S.p was the most common causative pathogen of CAP by MRT-PCR (21 cases, 23%). Causative pathogens of 12 cases (13%) were atypical bacteria such as L.p, M.p, and Chlamydophila pneumoniae. Virus infection rate was also high (22%). Conclusions: Compared with conventional tests, MRT-PCR was useful for diagnosing CAP. It can simultaneously identify ≥2 pathogens including atypical bacteria and uncultivable viruses and maintain high sensitivity in a large number of patients.
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