Abstract

We have conducted a multicenter study of the diagnostic accuracy of the MTBDRplus 2.0 assay in compared with conventional and molecular reference standard in four tuberculosis (TB)-specialized hospitals of China. A total of 5038 patients were enrolled in this study. The overall sensitivity of the assay for the diagnosis of TB was 92.7% [1723/1858, 95% confidence interval (95% CI): 91.5–93.9]. In smear-positive/culture-positive cases the sensitivity was 97.7% (995/1018, 95% CI: 96.6–98.6), whereas in smear-negative/culture-positive cases it was 86.7% (728/840, 95% CI: 84.2–88.9). The agreement rate between MTBDRplus 2.0 and Xpert MTB/RIF was 97.7% (1015/1039, 95% CI: 96.6–98.5) for smear-positive cases and 97.0% (3682/3794, 95% CI: 96.5–97.6) for smear-negative cases. As compared with phenotypic drug susceptibility testing, the MTBDRplus 2.0 correctly identified 298 of 315 patients (94.6%, 95% CI: 91.5–96.8) with rifampicin-resistance. As noted previously, isoniazid resistance is associated with many different mutations and consequently the sensitivity compared to phenotypic testing was lower (81.0%, 95% CI: 76.8–84.7). In conclusion, this assay is a rapid, accurate test in terms of increased sensitivity for detecting smear-negative TB patients, as well as an alternative for detecting both RIF and INH resistance in persons with presumptive TB, whereas the absence of a mutation in the specimens must be interpreted cautiously.

Highlights

  • Multidrug-resistant tuberculosis (MDR-TB), defined as resistance to at least isoniazid (INH) and rifampicin (RIF), poses as a major threat to global tuberculosis control[1,2,3]

  • All the cases with the valid results detected by both MTBDRplus 2.0 and Xpert Mycobacterium tuberculosis (MTB)/RIF were included in the comparison between these two methods, and there were 4833 cases included in the final analysis

  • There are several reasons responsible for this issue: (1) the implementation of rapid molecular assays for the detection of drug resistance is unsatisfactory in resource-poor settings with a high MDR-TB burden; (2) at present, all the molecular assays approved by the Chinese Food and Drug Administration are only approved for use on smear-positive clinical samples, including the endorsed Xpert MTB/RIF

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Summary

Introduction

Multidrug-resistant tuberculosis (MDR-TB), defined as resistance to at least isoniazid (INH) and rifampicin (RIF), poses as a major threat to global tuberculosis control[1,2,3]. Due to the slow growth rate of Mycobacterium tuberculosis (MTB), these methods always require several weeks to generate available results[8] This creates a diagnostic delay that increases morbidity and mortality for patients, and enhances transmission in the community[9]. In 2008, the GenoType MTBDRplus (Hain Lifescience, Germany) was approved by the WHO for the detection of MTB and for identifying rifampicin (RIF) and isoniazid (INH) resistance from cultured isolates and from smear-positive sputum samples[10, 11]. For smear-negative samples due to the requirement for prior bacterial culture Another endorsed molecular test platform for the detection of MTB and drug-resistance to RIF is Xpert MTB/RIF (Cepheid, USA)[12]. Our aim was to assess the performance of this assay for detecting TB and MDR-TB patients from persons with presumptive TB as compared with the conventional and molecular reference standards

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