Performance Assessment of Advansure™ MDR-TB Genoblot Assay Kit for Anti-tuberculosis Drug Susceptibility Test

Abstract

Background: Because of the long time required for conventional drug susceptibility test (DST) for rifampin and isoniazid, development of rapid DSTs is necessary. Recently, the AdvanSure™ MDR-TB GenoBlot Assay kit (LG Life Science, Korea), using reverse hybridization line blot assay, was developed. We compared this kit with Genotype ® MTBDRplus (HAIN Lifescience, Germany) and conventional DST. Methods: Of the DNAs preserved after performing DST by using Genotype ® , we selected 144 samples having conventional DST results. The experiments with both the kits were performed according to the manufacturers' instructions. For the samples for which discrepant results were obtained, sequencing was performed if the DNA was available. Conventional DST was performed at the Korean Institute of Tuberculosis by using the absolute concentration method. Results: For rifampin, the findings obtained using both the kits were the same with concordance rates of 98.6% (142/144) compared to conventional DST. Of the 2 discrepant findings, one was very major error and the other was major error. For isoniazid, compared to conventional DST, concordance rates of AdvanSure™ and Genotype ® were 95.8%(138/144) and 95.1%(137/144) respectively. Of the 6 discrepant findings between conventional method and Advansure™, 5 were very major error and one was major error. All the 7 discrepant findings between conventional method and Genotype ® were very major error. Conclusions: The findings obtained using AdvanSure™ showed high concordance with those obtained using Genotype ® and conventional DST. This kit has a higher rate of detection of isoniazid resistance because it includes probes for an additional target (ahpC).

Correlation between GenoType MTBDRplus Assay and Phenotypic Susceptibility Test for Prothionamide in Patients with Genotypic Isoniazid Resistance

“…Although the number of cases in this study was small, isolates with katG WT loss alone were all high-level INH resistant, while isolates with inhA WT loss alone were INH-resistant in only 25% of cases. Han et al 32 found one of 144 isolates showed low-level INH resistance with ahpC mutation confirmed by other LPA (AdvanSure MDR-TB GenoBlot assay), which revealed susceptibility to INH by conventional DST. The authors interpreted that the discrepancy might result from false positive of LPA, low-level resistance suppressing growth of M. tuberculosis at 0.2 µg/mL of INH, or hetero-resistance in which susceptible and resistant strains coexist.…”