소아에서의 마이코플라스마 폐렴의 진단을 위한 항체 검사에 관한 연구

Abstract

Background: Mycoplasma pneumoniae (MP) is one of the most common pathogens that cause community-acquired pneumonia in children world-wide. MP pneumonia occurs commonly in outbreaks every 3-4 years in Korea, of which the latest one occurred in 2011. Management of MP pneumonia is challenging because of the lack of the standard laboratory methods for rapid diagnosis. Various serologic tests and polymerase chain reaction (PCR) have been used with different diagnostic criteria. The database of 2011 MP pneumonia outbreak among children experienced in one university hospital was analyzed to delineate the optimal time for the indirect particle agglutination antibody test for a timely diagnosis of MP pneumonia to guide the proper management for patients with clinical features compatible with pneumonia. Methods: The study included 206 patients who were measured for MP antibody titers at initial presentation suggestive of pneumonia with fever and/or respiratory symptoms in the department of Pediatrics, Hanyang University Hospital, Seoul, Korea from June 2011 to October 2011. A database of 206 patients was obtained from medical records and retrospectively analyzed for demographic data and clinical laboratory test results including MP antibody titers, MP PCR, and respiratory virus PCR. Results: Among 206 patients cared for pneumonia, 160 children were diagnosed with MP pneumonia. The mean age of the patients with MP pneumonia was 5.44 ± 3.15 years and 61.9% were between ages 3 and 7. The duration between symptom onset to serum collection for the measurement of MP indirect particle agglutination antibody was different; 8.58days for the sera with MP antibody titer of ≥1:640 and 5.44 days for the sera with MP titer of < 1:640 (P < 0.001). In 42 MP pneumonia patients who were diagnosed by a 4-fold or greater rise of MP antibody titers in paired sera, the titers and the sampling dates after symptom onset distinctly differed between the first sera and the second sera; 1:125 ± 101 and 2–9 days (mean ± SD: 5.24 ± 1.71 days) for the first sera, 1:8,869 ± 8,288 and 6–15 days (mean ± SD: 10.45 ± 2.06 days) for the second sera. The optimum cutoff value for distinguishing between initial titer group and second titer group was 7.5 days after the onset of illness (sensitivity, 90.5%; specificity, 92.9%). MP PCR was performed in 90 patients with pneumonia and showed 64.4% agreement with serology (52.2% in positive results and 12.2% in negative results). Conclusions: The results of the study indicate that in children with pneumonia negative MP antibody titers obtained before 8 days after symptom onset require the repeat measurement to confirm the diagnosis. This suggestion will lead for optimal diagnosis and result in better therapeutic outcome of MP pneumonia. The diagnostic value of PCR may be against expectation for the diagnosis of MP pneumonia in children.