Objective: To study regimens containing isoniazid and rifampicin for the treatment of pulmonary tuberculosis with isoniazid or rifampicin resistance.
Methods: Eighty patients with isoniazid or rifampicin resistance, and whose sputum were still positive at the end of 2-month therapy with isoniazid (H), rifampicin (R), pyrazineamide (Z) and ethambutol (E), were retrospectively analyzed from Jan.2009 to Dec.2012 in Guangzhou Chest Hospital. According to the Mycobacterium drug sensitive test (DST) before the treatment with isoniazid and rifampicin, the patients were divided into the sensitive group (either H or R sensitive), the multidrug-resistance group (both H and R resistance) and the single-resistance group (H or R resistance). There were 80 patients (57 females, 23 males) whose sputum was still positive at the end of 2 month treatment. Their ages ranged from 16-80 (average 45) years. Among them, 29 received the first-treatment, while 51 received retreatment. There were 37 cases in the sensitive group, with 18 first-treatment patients and 19 retreatment patients. There were 15 cases in the single-resistance group, with 3 first-treatment patients and 12 retreatment patients. There were 28 cases in the multidrug-resistance group, with 8 first-treatment patients and 20 retreatment patients.
Results: After treatment, mycobacterial conversion to MDR-TB occurred in 2 patients in the sensitive group, and in 6 patients in the single-resistance group. The rate of conversion to MDR-TB was higher in the single-resistance group than that in the sensitive group (χ² = 12.849, P = 0.000).Six patients with single H resistance converted to MDR-TB and 2 patients with single R resistance converted to MDR-TB (P < 0.05, RR = 18.0).
Conclusions: Single H or R drug-resistance was more common in retreated patients with pulmonary tuberculosis.If regimens containing isoniazid and rifampicin was used to treat patients with single H or R drug-resistance, resistant enlarging effect may appear and lead to MDR-TB. The retreated patients should be monitored as soon as possible for detection of Mycobacterium resistance to H and R, and regimens for H or R-resistance should be used to prevent resistant enlarging effect.