Zombie Bacteria in Tuberculosis
Tuberculosis affects over 12 million people globally, and is usually treated with a course of four drugs over several months. However, even after completing the treatment, many patients suffer relapses. Based on studies of harmless environmental bacteria, scientists think that the tuberculosis bacterium, Mycobacterium tuberculosis, retreats into a bizarre “zombie” state in the patient’s body, and comes back to life when the conditions permit. Scientists at EPFL have now made the first experimental observation of M. tuberculosis in this zombie state, which seems to be amplified by stressful conditions such as attacks from the host’s immune system. The work, which points to entirely new pathways for treating tuberculosis, is published in Cell Host & Microbe.
Living bacteria divide and proliferate; if not, they are considered dead. However, some bacteria can go into a strange, in-between state where they are biologically active – producing energy and making proteins – but do not divide. “It’s a kind of living-dead, zombie existence,” said John McKinney, whose postdoc, Giulia Manina, led the study on M. tuberculosis. “The bacteria are somewhat active, but they’re neither growing nor dividing. We refer to this state as ‘Non-Growing but Metabolically Active’ or ‘NGMA’”.
