Absence of full drug-susceptibility data for TB patients can result in amplifying resistance: study

Based on data of TB drug-resistance profile by whole genome sequencing of 600 clinical samples from TB patients in India, the findings show that this can compromise treatment outcomes

The study notes that while TB stands as the second leading infectious disease killer globally with over 29.5 lakh active cases reported in 2020 alone in India, 1.35 lakh of these cases were classified as multi-drug resistant TB cases. Image for representation purposes only. File | Photo Credit: Getty Images/iStockphoto

In presumptive multi-drug resistant (MDR) tuberculosis cases, whole genome sequencing revealed that pre-extensively drug-resistant TB (pre-XDR-TB) was present in 50.83% of cases, while MDR-TB was found in 15.5% with nearly equivalent proportions among men and women, found a study conducted by an IIT Mumbai start-up in collaboration with Dr. D.Y. Patil Medical College, Pune.

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The comprehensive study, done by HaystackAnalytics, a start-up in the area of genomics diagnostic solutions, and Dr. D.Y. Patil Medical College, sheds light on TB dynamics in India and is based on real-world data on the TB drug-resistance profile by whole genome sequencing of 600 clinical samples from TB patients in India. The study indicates the clinicians’ reasons for sending samples for whole genome sequencing, which is for difficult-to-treat cases and/or relapse and treatment failure.

Extensively drug-resistant TB (XDR-TB) is a rare type of MDR-TB that is resistant to isoniazid and rifampicin, in addition to any fluoroquinolone and at least one of three injectable second-line drugs (i.e., amikacin, kanamycin, or capreomycin). Treating and curing drug-resistant TB is complicated.

The study notes that while TB stands as the second leading infectious disease killer globally with over 29.5 lakh active cases reported in 2020 alone in India, 1.35 lakh of these cases were classified as multi-drug resistant TB cases, thereby highlighting the significant challenge posed by drug-resistant strains to the efficacy of treatment and control measures.

The other key findings of 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 TB infection, but also to fluoroquinolones, which is used widely as therapy for respiratory and urinary tract infections.

Anirvan Chatterjee, CEO and co-founder at HaystackAnalytics and a contributor to this study, said that the findings underscore the urgency of revisiting the conventional ‘one size fits all’ approach to TB management.