Abstract: Objective To identify the genetic polymorphism and molecular epidemiological characteristics of Mycobacterium tuberculosis (TB) clinical isolates in Cangzhou, and explore the association between genotypes and drug resistance phenotypes. Methods Mycobacterium tuberculosis isolates were collected from TB patients treated in the Cangzhou Infectious Disease Hospital, and corresponding clinical data were also collected. The genomic DNA was extracted. Spacer oligonucleotide typing (spoligotyping) was applied to genotype the isolates. Drug susceptibility testing of first- line anti- TB drugs (streptomycin, isoniazid, rifampin, ethambutol) was performed using the BACTECTMMGITTM960 liquid medium. Cluster analysis was done by BioNumerics 5.0. Data was analyzed by Graphpad Prism 5.0 software. Results Of the 154 patients, 109 were male and 45 were female. And 121 patients were treated for the first time, 33 were retreatment, 34 had smoking history, 12 were complicated with diabetes mellitus. Fourty-eight strains (31.2%) were resistant to at least one of streptomycin, inoniazid, rifampicin and ethambutol. Initial drug resistance rate was 22.3% and acquired drug resistance rate was 63.6%. The drug resistance rate was significantly higher in retreatment patients than that of new cases. The Beijing family strain accounted for 91.6% of all isolates and the non- Beijing family strain accounted for 8.4% . There were no significant differences in gender, treatment history, smoking history and diabetes history between patients with the Beijing genotype and patients with non- Beijing genotype. Conclusion Mycobacterium tuberculosis in Cangzhou exhibits high genetic diversity. The Beijing genotype is the predominant no association with drug resistance.

Key words: mycobacterium tuberculosis, microbial sensitivity tests, epidemiology, molecular, cluster analysis, genotyping, spoligotyping