喀痰検体を用いた高処理ナノ流体PCR法による肺炎球菌血清型の同定・定量検査のワクチン血清型肺炎球菌性肺炎の診断精度について：複合的診断基準とベイズ潜在クラスモデルによる分析

The lack of reliable diagnostic tests for detecting vaccine serotype pneumococcal pneumonia (VTPP) remains a challenging issue in pneumococcal vaccine studies. This study assessed the performances of high-throughput nanofluidic PCR-based pneumococcal serotyping and quantification assay methods using sputum samples (the nanofluidic sputum quantitative PCR [Sp-qPCR] assay) to diagnose 13-valent pneumococcal conjugate VTPP compared with the performance of the serotype-specific urinary antigen detection (UAD) assay using urine samples. Adult pneumonia patients from Japan were enrolled in this study between September 2012 and August 2014. Sputum samples were subjected to the nanofluidic Sp-qPCR assay, quantitatively cultured, and serotyped by the Quellung reaction (SpQt). Urine samples were tested by the UAD method. The diagnostic performances of these tests were assessed using composite reference standards and Bayesian latent class models (BLCMs). Among 244 total patients, 27 (11.1%) tested positive with the UAD assay, while 16 (6.6%) and 34 (13.9%) tested positive with the SpQt and nanofluidic Sp-qPCR assays, respectively, with a cutoff value of ?104 DNA copies/ml, which showed the maximum value of the Youden index. Using BLCMs, the estimated prevalence for VTPP was 12.9%, and the nanofluidic Sp-qPCR assay demonstrated the best performance (sensitivity, 90.2%; specificity, 96.9%), followed by UAD (sensitivity, 75.6%; specificity, 97.9%) and SpQt (sensitivity, 45.8%; specificity, 99.5%). However, when a higher cutoff value of ?107 DNA copies/ml was applied, the performance of UAD became comparable to that of Sp-qPCR. The vaccine serotype-specific pneumococcal DNA load in sputum among UAD-positive patients was 3 logs higher than that among UAD-negative patients (P = 0.036). The nanofluidic Sp-qPCR assay may be accurate and useful for detecting VTPP among adults.長崎大学学位論文 学位記番号:博(医歯薬)甲第1102号 学位授与年月日:平成30年9月30日Author: Satoshi Kakiuchi, Motoi Suzuki, Bhim Gopal Dhoubhadel, Akitsugu Furumoto, Hiroyuki Ito, Kei Matsuki, Yoshiko Tsuchihashi, Norichika Asoh, Michio Yasunami, Koya Ariyoshi, Konosuke Morimoto and on behalf of the Adult Pneumonia Study Group-Japan (APSG-J)Citation: Journal of Clinical Microbiology, 56(5), e01874-17; 2018Nagasaki University (長崎大学)課程博