Abstract: Objective To investigate the distribution characteristics and pattern of DR-TB in different types of suspected pulmonary MDR-TB patients and provide scientific evidence for MDR-TB control in Shenzhen. Methods All suspected MDR-TB found during October 2006 to April 2009 were investigated. Sputum smear, culture, bacterial identification and drug susceptibility test were performed for diagnosis of MDR-TB. Statistical analysis was made for the incidence rate of DR-TB and MDR-TB in different types of pulmonary MDR-TB patients. Results 406 isolated strains ofMycobacterium tuberculosiswere tested for drug susceptibility, 36.2% of them were diagnosed as MDR-TB; MDR-TB accounted for 45.1% and 33.2% respectively in 82 cases of initial and 310 cases of retreatment suspected MDR-TB cases. In the category of retreatment failure, the proportion of MDR-TB is the highest of 66.7%. Among 147 cases of MDR-TB, initial treatment, retreatment and new patients accounted for 28.6%, 70.1% and 1.3% respectively. Of the 77 cases of other DR-TB, initial and retreatment PTB accounts for 22.1% and 77.9% respectively. The MDR-TB and DR-TB proportion are both high in two categories under initial treatment group. MDR-TB constituted the highest portion in retreatment failure category under retreatment group. In MDR-TB cases, the highest frequency is resistance to HRS and HRES in initial treatment group and HR and HRES in retreatment group. For other DR-TB patients, the majority is single drug resistance with highest frequency in H and R resistance.  Conclusion s Retreatment group was the major category for MDR-TB occurrence, however, there are also high MDR-TB incidence in those with smear positive Results after 3 months treatment and those with initial treatment failure(in fact, these are already retreatment cases). Drug resistance is serious in both new and retreatment group. And other DR-TB is high risk population for MDR-TB.

Key words: tuberculosis, pulmonary/drug therapy, drug resistance, bacterial, Shenzhen city