Abstract: Objective To explore the negative conversion rates and cure rates of smear-positive pulmonary tuberculosis patients with initial treatment or re-treatment of directly observed therapy from different age groups, in order to provide evidence for the formulation and adjustment of directly observed therapy of smear-positive pulmonary tuberculosis patients under initial treatment or re-treatment. MethodDirectly observed therapy according to Guidelines for the Implementation of China's Tuberculosis Control Program (2008) was applied to 318 initially treated patients and 48 retreated patients with smear-positive sputum from a street of Shenzhen city during 2012 to 2016 and results of sputum smear were analyzed.Result sThe negative conversion rates and cure rates at the end of Month 2, 5 and 6 of initially treated patients were the highest with the age of fewer than 19 years, lower with the age of between 20 and 39 years and the lowest with the age of more than 40 years. The negative conversion rates and cure rates at the end of Month 2, 5 and 8 of re-treated patients were the highest with the age of more than 60 years, lower with the age of between 20 and 39 years and the lowest with the age of between 40 and 59 years.Conclusion In the smear-positive patients who received directly observed therapy, the highest cure rates were achieved in initially treated patients with the age of fewer than 19 years and in re-treated patients with the age of between 20 and 39 years. Both the initially treated and the re-treated patients with the age of more than 40 years were suffered to lower cure rates.

Key words: Pulmonary tuberculosis, Smear-positive sputum, Negative conversion rates, Cure rates