Abstract: Objective To investigate genotypes of mutidrug-resistant(MDR) M.tuberculosis strains By DNA fingerprinting technique,and to discuss their role in molecular epidemiology.Methods A pair of outer primers for the amplification of IS6110 sequence from M.tuberculosis was designed.DNA fingerprinting method was established and used to analyze the genotypes of 220 MDR-resistant M.tuberculosis clinical isolates.The data from all of the tests were performed cluster analysis,and molecular epidemiology analysis.Results According to analysis of the DNA fingerprinting patterns,220 strains of Mycobacterium tuberculosis isolated were all shown specific DNA fingerprinting patterns,which were highly variable.The number of DNA copies per strain varied from 3 to 18.The majority(205,93.2%) of the strains contained 6-13 copies,with a mean of 11 bands.Of 205 DNA fingerprinting patterns observed,162 were unique,indicating epidemiological independence.However,58(26.4%) strains clustered in 15 groups,each cluster consisted of 2-8 isolates with identical patterns,presumably representing cases of recent transmission.In particular,one distinct pattern within this DNA fingerprint group was shared,220 strains of M.tuberculosis isolated all found one 200bp molecular weight of pattern.Conclusion DNA fingerprinting technique might be effectively applicable as a tool for the detection of genotype of drug-resistant M.tuberculosis,and for the survey on molecular epidemiology of multidrug resistance tuberculosis(MDR-TB).

Key words: Drug resistance,multiple, Mycobacterium tuberculosis, Blotting,southern