Objective To analyze the drug resistance and drug resistance spectrum of drug-resistant pulmonary tuberculosis (DR-TB) patients in Lanzhou, Gansu province, explore their distribution, and provide evidence for the improvement of control strategies and individualized treatment.

Methods A retrospective study was conducted by using the data of DR-TB cases registered in Lanzhou from 2012 to 2025. Eligible cases were included for descriptive analysis to summarize resistance patterns of anti-tuberculosis drugs and the composition of drug resistance spectrum, and χ² test orFisher’s exact test was used for the comparisons between different resistance combinations and treatment categories.

Results A total of 397 DR-TB cases were included. The resistance rates to rifampicin (RFP) and isoniazid (INH) were 99.24% and 90.60%, respectively, while the resistance rates to ethambutol (EMB), ofloxacin (OFX), and kanamycin (Km) were 55.22%, 40.96%, and 5.16%, respectively. In 319 cases with results of key drug susceptibility testing, multidrug-resistant tuberculosis (MDR-TB) cases accounted for 89.66% (286/319). In the MDR-TB cases, 53.15% showed the classic RFP+INH resistance pattern, and approximately half exhibited resistance to three or more drugs, mainly EMB and OFX. The proportion of the RFP+INH+EMB resistance pattern was significantly higher in previously treated cases than in newly treated cases (29.85% vs. 18.42%; χ²=5.134, P=0.023).

Conclusion From 2012 to 2025, DR-TB in Lanzhou was characterized by high resistance to rifampicin and isoniazid, and MDR-TB was predominant. The resistance spectrum showed trends to multiple drugs and to second-line drugs. It is necessary to strengthen drug resistance surveillance, expand drug susceptibility testing coverage, and improve individualized treatment strategies.