TB is a global public health threat. In 2009, there were an estimated 9.4 million cases of TB and 1.8 million deaths from the disease. TB treatment regimens are often lengthy and complex, and multidrug-resistant (MDR) TB is emerging as a worldwide epidemic. TB is also one of the most common causes of death among people infected with HIV. PA-824 is an experimental drug developed for the treatment of TB. This study will evaluate the safety, tolerability, and pharmacokinetic (PK) drug interactions between PA-824 and EFV, LPV/r, or RIF.