The use of molecular line probe assay for the detection of resistance to isoniazid and rifampicin

Overview

The WHO End TB Strategy calls for the early diagnosis of TB and universal drug susceptibility testing (DST), highlighting the critical role of laboratories for rapidly and accurately detecting TB and drug resistance. Multidrug-resistant tuberculosis (MDR-TB) is a public health crisis and a major threat to global TB control. Globally in 2015, there were 480 000 new cases of MDR-TB and an additional 100 000 cases with rifampicin-resistant TB newly eligible for MDR-TB treatment.

WHO recommends the use of LPA as a rapid diagnostic test for detection of rifampicin and isoniazid resistance. The WHO recommended commercially available tests include GenoType MTBDRplus VER 1 and 2 (Hain Lifescience, Germany), Nipro NTM+MDRTB detection kit 2 (Nipro, Japan). The Hain version 1 and 2 assays include probes to identify Mycobacterium. tuberculosis complex (MTBC), and detect mutations in the rpoB gene (associated with rifampicin resistance); in the katG gene and in the inhA promotor region (associated with isoniazid resistance). The probes used are the same for both versions of the assay. The Nipro assay allows detection of MTBC and resistance to rifampicin and isoniazid. This assay also differentiates M. avium, M. intracellulare and M. kansasii from MTBC and from other non-tuberculous mycobacteria.