Performance evaluation of AnyplexII MTB/MDR/XDR for detection of first and second-line drug resistance in Mycobacterium tuberculosis

Abstract

Background: The Anyplex TM MTB/MDR/XDR (Seegene) detection assay is a real-time multiplex PCR that can detect Mycobacterium tuberculosis (M.tb) and resistance to first line drugs (Rifampicin (RIF) and Isoniazid (INH)) and second-line drugs (Fluoroquinolone and injectables). Currently rapid diagnosis of drug resistance is performed through molecular assays that have limited detection probes. Anyplex assay has a high number of probes that are used to detect first and second-line drugs. We compared the performance of Anyplex TM MTB/MDR/XDR with culture and Genotype MTBDRplus 2.0 (Hain Lifescience)for detection of M.tb drug-resistance to first and second-line drugs. Methods & Materials: We retrospectively sampled 34 culture isolates and prospectively collected 51 clinical sediments. The 34 culture strains were tested for RIF, INH, OFL (Ofloxacin) and kanamycin (KAN). Of the 51 clinical sediments evaluated, microscopy results were positive (45), negative (2) and scanty (1) while 3 had no results. The clinical sediments were further tested on Genotype MTBDRplus. DNA sequencing was performed on gyrA and eis genes detected by Anyplex TM MTB/MDR/XDR assay. Results: The concordance between culture and Anyplex TM MTB/MDR/XDR respectively for INH, RIF, OFL and KAN was 26/26 (100%), 26/27 (96.0%), 15/16 (81.25%) and KAN (63.6%). Clinical specimens had a concordance between Genotype MTBDRplus and Anyplex TM MTB/MDR/XDR for INH and RIF was 4/4 (100%) and 16/17 (85.7%). The specificity for RIF and INH in clinical sediments was 95.0% and 95.3% respectively. Analysis of discordant results of KAN resistant samples revealedeis-C12T mutation not detected by Anyplex TM MTB/MDR/XDR assay. Conclusion: Anyplex TM MTB/MDR/XDR has good overall performance for detection of drug resistance in culture and clinical sediments. High sensitivity and specificity for detection of INH makes it an alternative method to Genotype MTBDRplus which is based on conventional PCR.