Rifampicin (R) and isoniazid (H) are key first-line anti-tuberculosis drugs. Failure to detect resistance to these two drugs early results in treatment failure and poor clinical outcomes. The study purpose was to validate the use of the GenoType MTBDRplus line probe assay (LPA) to detect resistance to R and H in Mycobacterium tuberculosis strains directly from smear-positive sputum samples in India.
Method: Smear positive sputum specimens from 320 patients were subjected to LPA and results compared against those from conventional Lowenstein Jensen (LJ) culture and drug susceptibility testing (C&DST). All specimens with discordant R DST results were subjected to either sequencing of the rpoB gene and/or repeat DST on liquid culture (MGIT 960) at a National Reference Laboratory.
Results: Significantly higher proportion of interpretable results were observed with LPA compared to LJ C&DST (94% vs. 80%, p-value
Conclusions: LPA proved highly accurate in the rapid detection of R resistance. The reduction in time to diagnosis may potentially enable earlier commencement of the appropriate drug therapy, leading to some reduction of transmission of drug-resistant strains.
Neeraj Raizada; Sachdeva, K.S.; Chauhan, D.S.; Bharti Malhotra; Kishore Reddy; Dave, P.V.; Mundade, Y.; Pranav Patel; Ranjani Ramachandran; Ram Das; Rajesh Solanki; Wares, D.F.; Suvanand Sahu; O’Brien, R.; Paramasivan, C.N.; Dewan, P.K. A Multi-Site Validation in India of the Line Probe Assay for the Rapid Diagnosis of Multi-Drug Resistant Tuberculosis Directly from Sputum Specimens. PLoS ONE (2014) 9 (2) e88626. [DOI: 10.1371/journal.pone.0088626]