Performance of the MTBDRsl Assay in the Country of Georgia

• Type of Material: Article
• Authors: Nestani Tukvadze, National Center for Tuberculosis and Lung Diseases; Nino Bablishvili, National Center for Tuberculosis and Lung Diseases; Rusudan Apsindzelashvili, National Center for Tuberculosis and Lung Diseases; Henry Blumberg, Emory University; Russell Kempker, Emory University
• Language: English
• Date: 2014-02-01
• Publisher: International Union Against Tuberculosis and Lung Disease
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2014 The Union.
• Final Published Version (URL): http://dx.doi.org/10.5588/ijtld.13.0468
• Title of Journal or Parent Work: International Journal of Tuberculosis and Lung Disease
• ISSN: 1027-3719
• Volume: 18
• Issue: 2
• Start Page: 233
• End Page: 239
• Grant/Funding Information: This work was supported in part by the NIH Fogarty International Center [D43TW007124 and D43TW007124-06S1], and the Emory Global Health Institute.
• Keywords: Respiratory System; GENOTYPE MTBDRSL; Science & Technology; POPULATION-STRUCTURE; tuberculosis; DRUG-RESISTANT TUBERCULOSIS; Life Sciences & Biomedicine; line-probe assays; drug resistance; TIME; ETHAMBUTOL RESISTANCE; STRAINS; Infectious Diseases; 2ND-LINE; DIAGNOSTIC-ACCURACY
• Research Categories: Biology, Microbiology; Health Sciences, Public Health; Chemistry, Biochemistry

Abstract

SETTING: The country of Georgia has a high burden of multi- (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB). OBJECTIVE: To assess the performance of the Geno- Type® MTBDRsl assay in the detection of resistance to kanamycin (KM), capreomycin (CPM) and ofloxacin (OFX), and of XDR-TB. DESIGN: Consecutive acid-fast bacilli smear-positive sputum specimens identified as MDR-TB using the MTBDRplus test were evaluated with the MTBDRsl assay and conventional second-line drug susceptibility testing (DST). RESULTS: Among 159 specimens, amplification was adequate in 154 (97%), including 9 of 9 culture-negative and 2 of 3 contaminated specimens. Second-line DST revealed that 17 (12%) Mycobacterium tuberculosis isolates were XDR-TB. Compared to DST, the MTBDRsl had 41% sensitivity and 98% specificity in detecting XDR-TB and 81% sensitivity and 99% specificity in detecting OFX resistance. Sensitivity was low in detecting resistance to KM (29%) and CPM (57%), while specificity was respectively 99% and 94%. Median times from sputum collection to second-line DST and MTBDRsl results were 70-104 vs. 10 days. CONCLUSION: Although the MTBDRsl assay had a rapid turnaround time, detection of second-line drug resistance was poor compared to DST. Further genetic mutations associated with resistance to second-line drugs should be included in the assay to improve test performance and clinical utility.