Abstract: Objective To determine the relation between the date to positive (DTP) of Mycobacterium tuberculosis in sputum culture and the treatment outcome of pulmonary tuberculosis treatment.Methods 56 patients suffering from pulmonary tuberculosis were studied with consecutive sputum cultures and clinical follow up for assessment.Results Following initiation of antituberculous therapy 40 patients (group A) had a positive response to treatment, and the DTP of Mycobacterium tuberculosis using MB/BacT tube cultured in Bac T/ALERT 3D increased steadily. The other 16 patients (group B) had persistent ev idence of active disease and the DTP demonstrated little or no increase with tre atment unless an additional therapeutic intervention was implemented (surgery, a dditional administration via bronchoscope timely, or a change in medication). Conclusion The DTP was superior to clinical, radiographic, or conventional bacteriologic evaluation on anticipating treatment outcome. There was a close relation between the DTP and the overall response to treatment for pul monary tuberculosis cases.It would be a good clinical method to predict the trea tment outcome.

Key words: Mycobacterium tuberculosis, Pulmonary tuberculosi s