[Analysis of drug resistance to antituberculosis drugs of the first time retreated pulmonary tuberculosis patients in Shanghai].

Objective: To investigate antituberculosis drug resistance among the first time retreated pulmonary tuberculosis patients in Shanghai, and therefore to provide evidence for establishing retreatment regimen.

Methods: Analysis was conducted retrospectively on drug susceptibility tests to isoniazid, rifampin, streptomycin, ethambutol and para-aminosalicylates of the first time retreated pulmonary tuberculosis patients with a positive sputum culture in Shanghai Center for Disease Control from January 2002 to December 2004.

Results: The total drug resistance rate was 39.6%. The drug resistance rate in male and female patients was 38.5% and 44.4% respectively, the difference being not significant. The drug resistance rate in the young age group, the middle age group and the old age group were 50.0%, 41.6% and 34.6% respectively, the difference being not significant. The total drug resistance rates in the treatment failure group with standard initial chemotherapy and in the relapse group with standard regimen were both higher than in the relapse group with non-standard regimen (70.0%, 47.5%, 28.2%). So do the drug resistance rates of more than two drugs (70.0%, 18.3%, 6.4%). The multi-drug resistance rate of the failures with standard regimen was 70.0%, much higher than the relapses with standard regimen and the relapses with non-standard regimen. In relapses with non-standard initial therapy, the drug resistance rate of patients who received medications > or = 12 months was 55.0%, significantly higher than those treated for 1 - 5 months (13.0%). The drug resistance rate of patients who were treated with one to two drugs was lower than those treated with > or = 3 drugs, but no significant difference was observed (24.4% and 30.8%).

Conclusion: Drug resistance rate varies in different types of the first time retreated pulmonary tuberculosis patients due to the history of drug use, which indicates that the current standard retreatment regimen is probably ineffective for some patients.