Tuberculosis (TB) kills more than 4,500 people each day worldwide; approximately million TB deaths occurred in 2006 alone (WHO, 2008a). TB is second only to AIDS as the leading infectious disease–related cause of adult deaths. Although antibiotic treatment for TB was discovered more than half a century ago, an estimated one-third of the world’s popula- tion is currently infected with Mycobacterium tuberculosis (Keshavjee and Seung, 2008), and million new cases of active TB are estimated to occur around the world annually (WHO, 2008a). .
