Further detail of sputum specimen collection: A trained study nurse using airborne precautions will collect expectorated sputum from enrolled subjects. The sputum will be collected in a sealable container labeled with subject's study ID number and securely transported on the same day to the Irkutsk Dispensary TB Laboratory for GeneXpert MTB/RIF testing as available. As GeneXpert is a validated, WHO-approved test for M. tuberculosis screening, these results will be communicated directly to the treating physician by the trained study nurse, per standard of care. The remainder of investigations, including MIC testing, sequencing for drug-resistance mutation and spoligotyping for sublineage identification, will be experimental.