Diagnostic accuracy of a molecular drug susceptibility testing method for the anti - tuberculosis 1 drug ,

Diagnostic accuracy of a molecular drug susceptibility testing method for the anti-tuberculosis 1 drug, ethambutol: a systematic review and meta-analysis 2 Song Cheng, Zhenling Cui, Yuanyuan Li , Zhongyi Hu 3 1. Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Medical School, Tongji 4 University, Shanghai, China 5 2. School of Biology and Basic Medical Sciences, Soochow University, Suzhou, China 6 # Corresponding author: Zhongyi Hu, email: [email protected]; 7 * Song Cheng and Zhenling Cui contributed equally to this article 8 Abstract 9 Ethambutol (EMB) is a first-line anti-tuberculosis drug; however drug resistance to EMB has been 10 increasing. Molecular drug susceptibility testing (DST), based on the embB gene, has recently been 11 used for rapid identification of EMB resistance. The aim of this meta-analysis was to establish the 12 accuracy of molecular assay for detecting drug resistance to EMB. PubMed, Embase and Web of 13 Science were searched according to a written protocol and explicit study selection criteria. Measures of 14 diagnostic accuracy were pooled using a random effects model. A total of 34 studies were included in 15 the meta-analysis. The respective pooled sensitivity and specificity were 0.57 and 0.93 for PCR-DNA 16 sequencing that targeted the embB 306 codon; 0.76 and 0.89 for PCR-DNA sequencing that targeted 17 the embB 306, 406, and 497 codons; 0.64 and 0.70 for detecting M. tuberculosis isolates, 0.55 and 0.78 18 for detecting M. tuberculosis sputum specimens using the GenoType MTBDRsl test; 0.57 and 0.87 for 19 Pyrosequencing, and 0.35 and 0.98 for PCR-RFLP. The respective pooled sensitivity and specificity 20 were 0.55 and 0.92 when using the lower EMB concentration as the reference standard, 0.67 and 0.73 21 when using the higher EMB concentration as the reference standard, and 0.60 and 1.0 when using 22 multiple reference standards. PCR-DNA sequencing using multiple sites of the embB gene as detection 23 targets, including embB 306, 406 and 497, can be a rapid method to preliminarily screen for EMB 24 resistance, but does not fully replace phenotypic DST. Of the reference DST methods examined, the 25 agreement rates were the best using MGIT 960 for molecular DST and using PM on Middlebrook 26 7H10 media. 27 Introduction 28 Tuberculosis (TB) is one of the most serious infectious diseases in the world. According to the 2013 29 Global Tuberculosis report by the World Health Organization (WHO), in 2012 an estimated 450 000 30 people developed multidrug-resistant TB (MDR-TB) and there were approximately 170 000 deaths due 31 to MDR-TB worldwide [1]. MDR-TB and extensively drug-resistant tuberculosis (XDR-TB) are 32 among the greatest threats to the success of TB control in the world [2, 3]. Ethambutol (EMB) is one of 33 the first-line drugs included in the directly observed, treatment short-course antitubercular regimen 34 recommended by the WHO [3]. EMB is commonly used in combination with isoniazid (INH), 35 rifampicin (RIF) and pyrazinamide (PZA) to treat TB, particularly when treating MDR-TB and 36 XDR-TB [3]. EMB has also been found to protect companion drugs against resistance, particularly 37 INH [4]. Initially, EMB was effective for preventing treatment failures caused by M. tuberculosis 38 isolates resistant to other anti-tuberculosis drugs; however, the resistant rate of EMB has gradually 39 increased in some regions and is close to 50% in TB patients that are re-treated [5-7]. In China, the 40 JCM Accepts, published online ahead of print on 4 June 2014 J. Clin. Microbiol. doi:10.1128/JCM.00560-14 Copyright © 2014, American Society for Microbiology. All Rights Reserved.