Abstract: Objective To investigate the epidemiologic characteristic of multidrug-resistant (MDR) Mycobacterium tuberculosis(MTB) in Shenzhen.Methods According to the standard of WHO, International Union Against Tuberculosis and Lung Disease (IUATLD), drug-susceptive and MDR MTB strains were collected by drug susceptibility test (DST) of 1% proportion method.kat G,inh A, intergenic region ofoxy R- ahp C and 81bp core region ofrpo B genes in 153 drug-susceptive strains and 132 MDR strains were analyzed by DNA sequencing.  Results 27.5%（42/153）of drug-susceptive strains and 98.5%（130/132）of MDR strains showed gene mutations. Of 132 MDR strains, 73.5%（97/132）had kat G mutations, and 68.9%（91/132）of kat G mutations were at codon 315; 18.2%（24/132）had inh A mutations, and none specific mutations were found at codon 94 of inh A; 11.4%（15/132）had mutations at inh A-promoter region; 16.7%（22/132）had ahp C mutations, 10.6%（14/132）had mutations at intergenic region of oxy R- ahp C; 93.2%（123/132）had mutations at the 81bp core region of rpo B.  Conclusion The codon 315 of kat G, promoter region of inh A,ahp C and the 81bp core region of rpo B play predominant roles in MDR-TB in Shenzhen.

Key words: Mycobacterium tuberculosis, Drug resistance,mutiple,bacterial, sequence analysis,DNA, mutation, Shenzhen city