Abstract: Objective To study the relationship between Km gene mutation and the drug-resistant M.tuberculosis.Methods 127 M.tuberculosis strains isolated from clinical sputum specimens were analyzed by traditional drug susceptibility tests and PCR-SSCP to be compared with their kanamycin drug-resistance and Km gene mutation.Results The rate of drug susceptibility tests was 35.4%(45/127).The electrophoresis profiles of 16S rDNA PCR-SSCP indicated that the 127 M.tuberculosis strains were according to M.TB standard strain.12 of the 45 kanamycin drug-resistant strains(26.6%) displayed abnormal in PCR-SSCP profiles.Conclusions In some degree,the reason why a certain M.tuberculosis strains indicate resistance to some second-line kanamycin drugs is because of the Km gene mutation of them.

Key words: M.tuberculosis, Drug-resistance, Kanamycin, Km gene