This is important to India where TB is endemic, widespread and resistant to even multi-drug treatment.
In what is being perceived as a significant breakthrough in the fight against TB, Bikul Das, an Indian researcher at Stanford University has discovered why it is difficult to completely eliminate the TB bacteria even after rigorous treatment.
In a study published in the journal, Science Translational Medicine, Das, who has been researching the subject for the past 15 years, points out that TB bacteria hide in a group of stem cells inside the bone marrow beyond the reach of antibiotics and the body's own immune system. These, he says, might reappear once the coast is clear and do a lot of damage. In fact, the bacteria take advantage of the body's own mechanisms of self-renewal.
Deepjyoti Kalita, a professor of microbiology with Gauhati Medical College and co-author of the study, calls it a landmark find. "We never knew where TB bacteria used to hide; but now that we know that the bacteria invade and hide in stem cells in the bone marrow, it would be possible to hunt them down and kill them in future. The present medicines don't help much in this respect."
Although considered "curable" to a large extent, TB still kills 1.9 million people across the globe. At present, the most popular treatment for the disease in India is the DOTS regimen, which takes six months to ameliorate the symptoms. But it fails to completely wipe it out, which is why relapses years or decades after the initial treatment are commonplace.
In his research, Das and his team studied the Idu-Mishimi community of Arunachal Pradesh that has a very high occurrence of TB. The team not only found genetic material from bacteria inside the stem cells, they were also able to isolate active bacteria from the cells from TB patients who had undergone extensive treatment for the disease. They say the findings indicate that other infectious agents may also employ similar "wolf-in-stem-cell-clothing" tactics.
"We now need to learn how the bacteria find and infect this tiny population of stem cells, and what triggers it to reactivate years or decades after successful treatment of the disease," says Das.
Many physicians treating TB are upbeat about the findings. Ashwini Khanna of Loknayak Hospital, Delhi, says he hasn't seen the research, but terms it as 'being full of promise.' "This might propel further research and change the way TB is treated across the globe," he says.
However, Praveen Pandey, a pulmonologist with Escorts Hospital, advises caution. "It may be possible to identify, isolate and kill TB bacteria even before they cause any problem; but there is also the risk of over-treatment. There could be a rush of people willing to be treated without any need for it."