Abstract: Objective To investigate the isolation rate of drug-dependent Mycobacterium tuberculosis in Guangzhou, and to provide scientific evidence for the clinical treatment.  Methods 3 911 M. tuberculosisstrains isolated and identified were analyzed the dependence on 11 frequently-used drugs (including Rifampin R, Isoniazid H, Streptomycin S, Ethambutol E, Ciprofloxacin C, Levofloxacin Lfx, Amikacin Am, Prothionamide Pto, Moxifloxacin M, Clarithromycin Clr, Dipasic D) using L-J drug susceptibility test.   Results Of 3 911 M. tuberculosisisolates, 192 strains isolated from 159 patients had dependence on 10 of 11 drugs, the isolation rate was 4.9% (192/3 911).  Among  these, the isolation rate of dependence on R was 2.7% (104/3 911), H was 2.4% ( 92/3 911 ), S was 1.0% (38/3 911), C was 0.4% (16/3 911), Lfx was 0.3% (12/3 911), Am was 0.3% ( 10/3 911 ), E was 0.2% (8/3 911), and Pto was 0.1% (5/3 911), both of Mfx and Clr were 0.1% (3/3 911), respectively. Dependence upon Dipasic was not observed. Of 159 patients, 25 were extensively drug-resistant TB (XDR-TB), and 110 were multiple drug-resistant TB (MDR-TB), accounting for 84.9% (135/159) cases of drug-dependent TB.  Conclusions The drug-dependence ofM. tuberculosisin Guangzhou was primarily upon R and H, whereas dependence rate upon Mfx and Clr were the lowest. Furthermore, the majority of drug-dependent TB was MDR-TB or XDR-TB.

Key words: Mycobacterium tuberculosis, drug resistance,mutiple,bacterial