The conventional approach to treating tuberculosis (TB) needs to be revisited given the presence of different genetic lineages, and doctors need to be aware when to send patients for whole genome sequencing (WGS), so treatment could be more targeted.

These were the takeaways from a recent study undertaken by HaystackAnalytics, a genomics diagnostic solutions firm and Pune’s DY Patil Medical Hospital. The study was based on the TB drug-resistance profile by whole-genome sequencing of 600 clinical samples from patients with TB in India.

“Our study underscores the urgency of revisiting the conventional, one size fits all approach to TB management,” said Dr Anirvan Chatterjee, Co-founder and Chief Executive, HaystackAnalytics, and a contributor to the study.

Doctors need to send patients for WGS when they are showing resistance to certain drugs, to be able to tailor the individual’s treatment, Chatterjee told businessline, adding that, otherwise it could lead to further drug resistance. “When anti-TB therapy is given in the absence of a complete drug resistance profile, such a therapy may contain one or more drugs to which the patient is resistant to, and could compromise the outcome of the therapy,” he said.

Besides this, “understanding the genetic lineages, particularly the predominance of the Beijing genotype, followed by Delhi-CAS and EAI, is crucial for developing targeted interventions and treatment strategies,” a note from the company said.

India bears 27 percent of the total TB cases in the world, according to the Global TB Report 2023. Tuberculosis is the second leading infectious disease killer

globally, with over 2.95 million active cases reported in 2020 alone in India. Among these cases, 135,000 were classified as multidrug resistant TB cases.

Study findings

The study highlighted resistance not only to rifampicin, a drug used to manage and treat diverse mycobacterial infections, and isoniazid, an antibiotic indicated in the first-line treatment of active Mycobacterium tuberculosis (TB) infection, but also to fluoroquinolones, used as therapy for respiratory and urinary tract infections. Also, 55 percent in the 15-35 years age group and 67 percent in the age group up to 14 years had pre-XDR TB, a note on the study said.