Performance Assessment of the GenoType MTBDR plus Test and DNA Sequencing in Detection of Multidrug-Resistant Mycobacterium tuberculosis

Abstract

To facilitate the management of multidrug-resistant (MDR) tuberculosis, two nucleic acid sequence-based methods, the GenoType MTBDRplus test and DNA sequencing, were assessed for the rapid detection of drug-resistant Mycobacterium tuberculosis for the first time in the Asia-Pacific region. The performances of these two assays in detecting the presence of rifampin (rifampicin) (RIF) and isoniazid (INH) resistanceassociated mutations in the rpoB, katG, inhA regulatory region, inhA, and oxyR-ahpC genes were compared to that of a conventional agar proportion drug susceptibility test. A total of 242 MDR and 30 pansusceptible M. tuberculosis isolates were evaluated in this study. The sensitivities obtained for RIF-resistant detection by the GenoType MTBDRplus test and by resistance gene sequencing were 95.5% and 97.9%, respectively. The sensitivities for INH resistance detection by the GenoType MTBDRplus test and by resistance gene sequencing were 81.8% and 93.4%, respectively. Together, the sensitivity for MDR tuberculosis detection was 78.5% with the GenoType MTBDRplus test and 91.3% by resistance gene sequencing. The specificity for RIF resistance, INH resistance, and MDR detection was 100% by both methods. The GenoType MTBDRplus test has the advantage of a short turnaround time for drug-resistant M. tuberculosis detection. Overall, the two assays performed equally well in detecting RIF resistance (P ‫؍‬ 0.13). However, DNA sequencing demonstrated superior performance in detecting INH resistance (P < 0.001) and MDR tuberculosis (P < 0.001). We suggest that new alleles of INH resistance genes should be evaluated to improve the sensitivity of the GenoType MTBDRplus test, especially for different geographic areas with genetically diverse M. tuberculosis strains.

Predictive Value of Molecular Drug Resistance Testing of Mycobacterium tuberculosis Isolates in Valle del Cauca, Colombia

“…In our study, both susceptible and resistant, mainly MDR, M. tuberculosis strains were evaluated; unfortunately, only a limited number of strains resistant to second-line drugs were evaluated. We found the performance of the GenoType tests in Colombia to be similar to or even better than those described in studies elsewhere, like in Mexico, Brazil, Peru, Chile, Bolivia, France, Italy, Turkey, Spain, Vietnam, the Russian Federation, Ethiopia, and China (4,(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23). In general, sensitivity, specificity, positive and negative predictive values, and concordance with phenotypic DST support the utility of these tests for the screening of resistance to first-and second-line antituberculosis drugs in our country.…”

“…Some studies in China, Vietnam, and South Africa revealed that the most frequent mutations are D94G (gyrA) (36.5%) and A1401G (rrs) (42.1%) in China, D94G (54%) and A1401G (80%) in Vietnam, and D94G (42.4%) in South Africa; these were the most frequent mutations also detected in Colombian strains (4,21,26).…”

“…Previous evaluations of the GenoType kits have documented their performance in detecting resistance to first-and second-line antituberculosis (anti-TB) drugs in different continents, like Africa, Asia, and Europe (2,3,4,5). From these studies, it became clear that there are geographic variations in the mutations that are associated with drug resistance in Mycobacterium tuberculosis (6).…”

Molecular detection of rifampicin resistance in multidrug-resistant Mycobacterium tuberculosis strains from North-Eastern Romania

“…Furthermore, Mokrousov et al suggested that analysis of other rpoB hot spot codons in Russian region is insignificant for prediction of RIF resistance (5). Studies using other molecular techniques, such as Genotype MTBDRplus assay, identified 95.4% to 99% of RIF-resistant strains in China and South Africa, respectively (21,22). These regional differences could be explained by variations in relative frequencies of investigated mutations (5).…”

Evaluación de la técnica Xpert® MTB/RIF para la detección de Mycobacterium tuberculosis complex en muestras extra-pulmonares

“…La detección de MTBc por técni-cas moleculares es de gran utilidad porque ha permitido un diagnóstico más rápido respecto del cultivo y más sensible con respecto a la baciloscopia, desarrollándose en los últimos años, varias pruebas diagnósticas [7][8][9][10][11][12] . Una de estas es el ensayo Xpert ® MTB/RIF, que se realiza en el sistema GeneXpert ® (Cepheid, Sunnyvale, CA).…”