Abstract: Objective  To investigate the situation of the sputum conversion after two months treatment of retreated smear-positive pulmonary tuberculosis patients registered in 2011—2012, and to explore the influencing factor and their effects on treatment outcome. Methods  Acid-fast staining and microscopic examination were performed twice on 131 retreated smear positive tuberculosis patients registered in the Second Outpatient Department of Guangzhou Thoracic Hospital. Absolute concentration method was used on the culture positive samples for drug resistance test and related factors on sputum conversion were also investigated.  Results  Among the 131 retreated patients, 91 showed sputum conversion, and 27 showed non-conversion after 2 months of treatment (sputum examinations were not performed on 13 of the patients due to their unavailability of the patients). There were 15, 6, and 6 patients showed sputum conversion after 3 months, 4 months, and 5 months treatment respectively. After analyzing 5 variable factors, we found that the main reasons for non-conversion after 2 months treatment in retreatment smear-positive pulmonary tuberculosis were poly resistance (5.3%，3/57) for patients with sputum conversion and 10.0% (2/20) for non-conversion patients) (χ²=4.457, P<0.05) or multidrug-resistance (28.1%，16/57) for patients with sputum conversion and 70.0% (14/20) for non-conversion patients) (χ²=5.456, P<0.05), or with diabetes mellitus (12.1%，11/91) for patients with sputum conversion and 25.9% (7/27) for non-conversion patients) (χ²=3.973, P<0.05). Conclusion sputum non-conversion after 2 months treatment is found to be closely related to drug resistance or with diabetes mellitus.

Key words: Tuberculosis, pulmonary/drug therapy, Treatment outcome