Abstract: Objective To investigate the distribution and drug resistance of pathogens in multidrug-resistant pulmonary tuberculosis patients with lower respiratory tract infection.  Methods From January 2007 to December 2009, 127 multidrug-resistant pulmonary tuberculosis patients with sputum culture-positive lower respiratory tract infection and 432 first medicina treatment of pulmonary tuberculosis patients with sputum culture-positive lower respiratory tract infection were examined for bacterial identification and susceptibility test, then analysis.  Results A total of 157 pathogenic bacteria strains were isolated from 127 cases of multidrug-resistant pulmonary tuberculosis with lower respiratory tract infection.Among them, Gram-negative bacillus was in the first place, accounting for 67.5%, followde by Fungi accounted for 30.5%, Gram-positive bacteria 2%. Compared with the first medicina treatment of pulmonary tuberculosis patients,ratioof opportunistic Gram-negative bacillus in patients with multidrug-resistant pulmonary tuberculosis, Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae, Acinetobacter,was significantly higher.However, ratioof less resistant pathogens, Haemophilus parainfluenzae,in MDR patients was significantly lower than that of patients with the first medicina treatment of pulmonary tuberculosis,it was statistically significant difference between the two groups (P<0.05).Ratio of Fungal infection(30.5%) in patients with multidrug-resistant pulmonary tuberculosis is significantly higher than that of first medical treatment of pulmonary tuberculosis patients (20.6%)（P<0.05）.Gram-positive cocci infection rate of MDR patients is lower than that of first medical treatment of pulmonary tuberculosis patients,it was statistically significant difference between the two groups (P<0.05). Mixed infection rate increased in MDR patients (P<0.05).Gram-negative bacteria susceptibility showed theThe third generation of the above cephalosporins, carbapenems, quinolones had more sensitive, the bacterial resistance level was incresed between the two groups (P<0.05). Gram-positive cocci to penicillin, clindamycin resistance rates was higher, more sensitive to vancomycin.  Conclusion The primary pathogenic bacteria was Gram-negative opportunistic pathogen in lowerrespiratory tract of the patients with lower infection MDR pulmonary tuberculosis,and drug resistance is serious, fungal infection and mixed infection rate increased. Clinical attention should be paid bacterial culture and sensitivity test, to reduce irrational drug use, aggressive treatment of complications, reduce the mixed infection.

Key words: tuberculosis,pulmonary, tuberculosis,multidrug-resistant, drug-resistance,multiple,bacterial