A recent report by the World Health Organization estimates that about two million deaths occur every year due to tuberculosis (TB). An alarming dimension to this problem is the fact that some strains of Mycobacterium tuberculosis (Mtb), the causative agent of TB, have developed resistance to some antibiotics used to kill them, leading to the emergence of ‘drug resistant TB’ and causing a global threat. Drug resistance is a way by which bacteria respond to the drug stress they face. Due to improper and irregular use of antibiotics by patients, not all bacteria may be killed, leading to the emergence of drug resistant strains that survive even when further doses of the drug are administered. Now, a team of researchers at the Indian Institute of Science, Bangalore, led by Prof. Nagasuma Chandra and Prof. Amit Singh, have explored the mechanism behind the development of resistance to a front-line anti-tubercular drug called isoniazid, used widely in the clinic.