Abstract

Tuberculosis is a major infectious diseases in Asia, Africa and South American continents killing more than 2 million people every year. An accurate and rapid diagnosis is urgently required for better management and control of this killer disease.

 

Even though GeneXpert assay has changed the diagnostic scenario in last few years, due to its ability to diagnose a case of TB within 2 hours and innovative sample processing protocol, but its cost is a major challenge.  Several other molecular tests are also in pipeline, or in evaluation stage and some are already endorsed, such as line probe assay (LPA). But molecular tests will ever be taken for screening of the suspected TB patients is a big question. The conventional smear and culture based phenotypic detection methods have inherent limitation of low sensitivity and longer turn around time. Recently our laboratory has discovered 4 novel antigens of M. tuberculosis which are highly overexpressed during the acquisition of multi-drug resistance.  To scale up, the recombinant antigens were prepared and evaluated on the clinical samples using ELISA, and western blot tests. The results showed that pooled sensitivity (75-97%) and specificity (89-98%) was very high. We also found that in HIV positive patients with MDR-TB the sensitivity was as high a 100% (Singh et al, 2017 Nature Scientific Reports, doi:10.1038/srep44121).

 

However, the ELISA and Dot blot tests are not field friendly and require technical skill and laboratory instrumentation. Therefore, we are in the process of developing point of care rapid tests using these recombinant antigens and looking forward for public private partnership for commercialization of these antigens.