ABSTRACT
Objective To establish the molecular characteristics of Mycobacterium tuberculosis and on factors influencing the recent transmission of drug resistant isolates in Shandong. Methods Mycobacterium tuberculosis isolated from active pulmonary tuberculosis patients of 13 counties were genotyped by mycobacterial interspersed repetitive units (MIRU) methods. Results 12 loci of MIRU were detected in 558 isolates and a total of 143 MIRU patterns were confirmed. 66 isolates had distinct patterns,and 481 (86.2%) strains were in clusters. Shandong cluster included 177 strains with 74.6% of the isolates belonged to Beijing family. The recent transmission index of multi-drug resistance strains was in lower level,comparing to the susceptible strains. Conclusion Our results showed that the Shandong cluster isolates had capacities of facilitating person-to-person transmission and high level of drug resistance.