Abstract: Objective  To analyze the situation and risk factors of drug resistance(DR) of Mycobacterium tuberculosis (Mtb) among patients in Xi’an Tuberculosis and Thoracic Tumor Hospital retrospectively. Methods  From January 2008 to December 2012, a total of 4721 sputum culture positive patients visited the Xi’an Tuberculosis and Thoracic Tumor Hospital. Among these patients, 4238 (89.77%) were new patients and 483 (10.23%) were retreatment patients. We analyzed the drug susceptibility situation of their clinically isolated strains for 4 kinds of first line anti-TB drugs, namely streptomycin (S)、isoniazid (H)、rifampin (R)、ethambutol (E). The drug susceptibility test was carried out by absolute concentration method. Database were established using Excel. Statistical analysis was performed with SPSS 16.0 statistical software. Differences among groups were compared withχ² test. And the risk factors of total DR and multidrug-resistance (MDR) were also analyzed with Logistic regression analysis. P＜0.05 was considered statistically significance. Results  Among the 4721 sputum culture positive patients, the total DR rate, initial DR rate and acquired DR rate were 31.71% (149/4721), 27.35% (1159/4238) and 69.98% (338/483) respectively; the total MDR rate, initial MDR rate and acquired MDR rate were 12.20% (576/4721), 7.74% (328/4238) and 51.35% (248/483). The DR rates of the 4 kinds of first line anti-TB drugs were H (23.85%,1126/4721)、S (21.75%,1027/4721)、R(12.86%, 607/4721)、E(6.93%, 327/4721). In terms of resistance pattern, the majority were single-drug resistant (12.71%, 600/4721) and two kinds drug resistant (9.53%, 450/4721). DR and MDR rate of 20- and 40- were 31.13%,11.13% and 39.86%,18.65%, compared with <20 years, χ² values were 12.67,11.31 and 43.20,38.28, P value <0.05, OR value (95%CI) was 1.4（1.1-1.7）,1.4（1.0-2.1）and 2.2（1.7-2.8）,3.2（2.2-4.6）; DR and MDR rate of retreatment were 69.98% and 51.35%, compared with initial, χ² values were 274.48 and 715.3, P<0.05,OR values (95%CI) were 5.9（4.9-7.4）,13.7（10.9-17.2）; MDR of no DOTS was 11.29%,χ² values were 11.63, P<0.05,OR value (95%CI) were 1.4（1.1-1.6）.  Conclusion  The DR rate of Mtb in Xi’an Tuberculosis and Thoracic Tumor Hospital was relatively high. The patients from 20 to ＜60 were more likely to have DR and MDR and those who hadn’t received the DOTS strategies were more likely to have MDR.

Key words: Tuberculosis, pulmonary, Mycobacterium tuberculosis, Drug resistance, multiple, Risk factors, Xi&, rsquo, an city