Tuberculosis remains a big challenge

Tuberculosis (TB) is a communicable disease that is a major cause of ill health and one of the top 10 causes of death worldwide. According to WHO in 2019 a total of 1.5 million people died worldwide because of TB making it a major public health crisis. According to WHO, India reports for a quarter of all global and multidrug-resistant TB (MDR-TB) cases. Unfortunately, only 58% of overall estimated new and relapsing TB cases are notified in India.

According to the latest report by WHO, the number of people who were provided with TB preventive treatment had increased four times from 1 million in 2015 to over 4 million in 2019. However, the Covid-19 pandemic threatens to unwind the gains made over recent years. The impact of the pandemic on TB services has been severe since there is a sharp decrease in TB notifications in 2020 in the country like India where the TB burden is the highest.

Read | As Covid-19 rages, world risks losing tuberculosis gains

In an annual report issued by the Ministry of Health and Family Welfare (MoHFW), India TB Report 2020, it was reported that up to four lakh TB patients went missing or unreported. There is an urgent need for both private and public health care sectors, to collaborate and build a strong surveillance system with a proper framework for notifying new, existing, missing and relapsed patients.

The early accurate diagnosis followed by prompt appropriate treatment is vital for ending TB. The conventional detection of TB is through microscopic examination in the smears of clinical specimens. Although smear remains the mainstay for diagnosis in resource-poor countries, it cannot easily differentiate between the Mycobacterial species. Culture-based identification although the gold standard, is time-consuming, requiring 2–6 weeks to produce results and is labour-intensive. WHO recommends the use of Nucleic Acid Amplification Tests (NAAT) as the initial diagnostic test for TB.

Among the currently available NAAT, the Xpert MTB/RIF Assay (CB-NAAT), the Line Probe Assay (LPA) and the Loop-Mediated Isothermal Amplification (LAMP) are endorsed by WHO for in vitro diagnosis of TB. These popular tests are excellent for rapid detection of Mycobacterium tuberculosis and screening of drug resistance. However, there is still a gap in the market that accurately profiles drug resistance mechanism for the causative organism in a TB patient, which can help the treating clinician take an informed decision on which treatment regimen to be prescribed.

While phenotypic drug susceptibility test provides physical proof of whether the drug will act or not on a culture grown from the patient’s sample, sophisticated molecular techniques provide a much-detailed view of the infection. Keeping in mind this burning issue, we have developed a test that sequences the entire genome of the causative organism from the sputum sample directly and performs drug resistance profiling. Because it is as easy as spitting and then sequencing, we have named the test “SPIT-SEQ”.

SPIT SEQ is a comprehensive approach that does direct sputum based whole genome sequencing test for diagnosis and drug resistance profiling in pulmonary tuberculosis. This test provides insights to the treating clinician for informed treatment decisions that are tailored as per the causative organism of an individual TB patient. In a country where we have a significant number of MDR-TB patients, SPIT SEQ fits as the best solution as it gives a detailed analysis of drug resistance-related mutations present in any TB bacteria causing drug resistance. The phenotypic drug susceptibility test that is currently used for drug resistance profiling is more time consuming and do not provide data regarding the gene mutations which are associated with drug resistance.

Just like many other infectious diseases, TB has also been sidelined due to the Covid-19 pandemic. However, the pandemic did teach us the importance and need for faster and accurate molecular diagnostics and the infrastructure required for it. This pandemic has also shown that how governments, public and private health care organizations, professionals, and policymakers have come together—to fight against Covid-19. I believe that lessons learnt from Covid-19 pandemic should be applied to TB. Thus, the medical infrastructure for TB diagnosis and prognosis should be reworked upon based on learnings and innovations brought in due to Covid-19.

(The writer is CEO, MedGenome Labs)