Abstract: Objective To study mycobacterium species and drug susceptibility of mycobacteria isolated from 2001 to 2004 in Guangzhou,and to provide reliable scientific support for clinical diagnosis and therapy of tuberculosis.Methods 2154 mycobacterial strains isolated from 1459 patients from Sep 2001 to Mar 2004 were identified the species and the susceptibilities to 4 antituberculosis drugs by absolute concentration methods.Results The positive ratio of nontuberculous mycobacterium increased from 16.5% during Jul 1998 to Sep 2001 to 20.5%.The Results of drug susceptibilities of 1703 Mycobacterium tuberculosis isolates showed that the primary drug resistance rate increased from 14.4% during Jul 1998 to Sep 2001 to 20.1% and the secondary drug resistance rate decreased from 35.4% to 32.6%.However,non-tuberculous mycobacteria showed high primary resistance to antituberculosis drugs.Conclusions It is necessary that mycobacteria isolated from clinical samples should be identified the species and performed drug susceptibility tests.

Key words: Mycobacterium tuberculosis, Drug resistance, Mycobacteria,non-tuberculosis