Lei Zhang, Ph.D., and Michael Niederweis, Ph.D., of the University of Alabama at Birmingham have made what they call "a major step" in understanding how Mycobacterium tuberculosis acquires iron from its human host—a process essential for the pathogenesis of this bacterium. Tuberculosis kills more than 1 million people each year, but without iron, M. tuberculosis cannot grow.
source https://www.lifetechnology.com/blogs/life-technology-science-news/a-gene-in-tuberculosis-bacteria-is-found-essential-for-siderophore-secretion-and-virulence