MDR-TB and extensively-drug resistant (XDR-TB) tuberculosis is a critical problem globally (LoBue 2009). It is estimated that the global proportion of resistance among all tuberculosis cases is 4.8%. China, India, and the Russian Federation combined have the highest number of MDR-TB cases: China and India account for approximately 50% of the global burden and the Russian Federation accounts for an additional 7% (Wright and Zignol 2008). The population-weighted mean of MDR-TB among all TB cases is 5.3%, but ranges from 0% in some western European countries to more than 35% in some countries of the former Soviet Union (Wright and Zignol 2008). The highest proportions of TB cases are resistant to isoniazid and streptomycin, followed by rifampicin and ethambutol (Wright and Zignol 2008). Isolated resistance to fluoroquinolones has also been documented (Long et al. 2009). Increased incidence of pulmonary cavities is associated with MDR-TB (Aguiar et al. 2009). Drug-resistant TB disproportionately affects young adults (Palacios 2009); previous failed treatment, recent relapse, and homelessness are all associated with MDR- and XDR-TB.