Novel Wide-Range Quantitative Nested Real-Time PCR Assay for Mycobacterium tuberculosis DNA: Clinical Application for

Although the “gold standard ” for diagnosis of tuberculous meningitis (TBM) is bacterial isolation of Mycobacterium tuberculosis, there are still several complex issues. Recently, we developed an internally con-trolled novel wide-range quantitative nested real-time PCR (WR-QNRT-PCR) assay for M. tuberculosis DNA in order to rapidly diagnose TBM. For use as an internal control calibrator to measure the copy number of M. tuberculosis DNA, an original new-mutation plasmid (NM-plasmid) was developed. Due to the development of the NM-plasmid, the WR-QNRT-PCR assay demonstrated statistically significant accuracy over a wide detec-tion range (1 to 105 copies). In clinical applications, the WR-QNRT-PCR assay revealed sufficiently high sensitivity (95.8%) and specificity (100%) for 24 clinically suspected TBM patients. In conditional logistic regression analysis, a copy number of M. tuberculosis DNA (per 1 ml of cerebrospinal fluid) of>8,000 was an independent risk factor for poor prognosis for TBM (i.e., death) (odds ratio, 16.142; 95 % confidence interval, 1.191 to 218.79; P value, 0.0365). In addition, the copy numbers demonstrated by analysis of variance statistically significant alterations (P < 0.01) during the clinical treatment course for 10 suspected TB