Molecular epidemiological characteristic study on transmission of Mycobacterium tuberculosis.

OBJECTIVE To establish the molecular characteristics of Mycobacterium tuberculosis and the impact factor of recent transmission of drug resistant isolates.METHODS M.tuberculosis isolated from positive patients of 13 counties,were genotyped by Mycobacterial Interspersed Repetitive Units(MIRU)methods.RESULTS Twelve loci of MIRU were detected in 558 isolates,and a total of 143 MIRU patterns were confirmed.Seventy-seven isolates had distinct patterns,and 481(86.2%)strains were in clusters.Shandong Cluster included 177 strains and 74.6% isolates belonged to Beijing family.The recent infection estimate value of multidrug-resistant strains was in lower level compared to the susceptible ones.CONCLUSIONS The Shandong cluster isolates have high capacity of person-to-person transmission,and a high level drug resistance;National TB Control Program should be further strengthened in genotyping survillence to address these problems.