Abstract

EVALUATION OF THE GENOTYPE MTBDRPLUS ASSAY FOR RIFAMPIN AND ISONIAZID SUSCEPTIBILITY TESTING OF MYCOBACTERIUM TUBERCULOSIS STRAINS IN SPUTUM SPECIME

Sita Ram Sapkota*, Bhawana Shrestha, Nikhil Ghimire and Pradeep Kumar Shah

Abstract

Rapid line probe assay (LPA) can be a practical and rapid alternative to the slow conventional phenotypic drug susceptibility testing (DST) for detection of drug resistant tuberculosis (TB). The purpose of this study is to determine the diagnostic accuracy of Genotype MTBDRplus, LPA for TB. A total of 85 culture samples were analyzed for evaluation MTBDRplus, assay A commercially available new Genotype MTBDRplus assay (Hain Lifescince, GmBH, Nehern, Germany) was evaluated for its ability to detect mutations in Mycobacterial isolates conferring resistance to rifampin (RMP) and isoniazid (INH). A total of 85 Samples were analysed in which 5 non tuberculoid mycobacteria strains, 55 multidrug resistant (MDR; i.e., at least resistant to RMP and INH), 24 fully susceptible strains were analyzed using Genotype MTBDRplus assay. MTBDRplus assay was designed to detect the mutations in the regulatory region of inhA. The MTBDRplus assay detected 55 of 80 RMP resistant strains (68.75%) with mutations on 81- bp hot spot region of rpoB gene and 48 of 50 of 2 INH resistant strains (96%) with mutation in codon 315 katG and regulatory region of inhA. In conclusion, the new Genotype MTBDRplus assay represents a rapid, reliable, upgraded tool for the detection of INH and RMP resistance strains that can readily be included in a routine laboratory work for the early diagnosis and control of MDR-TB.

Keywords: MDR-TB, Genotype MTBDRplus assay, RMP, INH, rpoB, katG, inhA.