This study is a prospective observational cohort study. MDR-TB patients from multi-centers in China were continuously evaluated one by one, their close contacts were screened for elibgility. All subjects were followed for the same length of time: 80 weeks after enrollment. The symptoms and signs of tuberculosis were followed up to monitor the occurrence of tuberculosis.~The primary objective is to investigate the incidence of etiologically confirmed or clinically diagnosed active TUBERCULOSIS in close contacts of MDR-TB patients.~The secondary objective is to assess latent TB infection rates in close contacts of MDR-TB patients; evaluate the high risk factors of TUBERCULOSIS in close contact population; assess the loss rate of close contacts within 80 weeks; assess the 80-week mortality rate among close contacts; isolate the mycobacterium tuberculosis from all patients with active tuberculosis and analyze drug resistance to evaluate the homology and drug-resistant transmission pattern of Mycobacterium tuberculosis.
To investigate the incidence of etiologically confirmed or clinically diagnosed active tuberculosis in close contacts of MDR-TB patients.