Abstract: Objective To investigate the characteristics of the distribution and drugresistance of pathogenic bacteria in lower respiratory tract of severe pulmonary tuberculosis cases. Method The positive culture from protected specimen brush viabranchofibroscope from 82 cases with severe pulmonary tuberculosis were perfomed for gemspecies identification and drug sensitivity test in vitro. Results Total 98 pathogenicbacteria strains were found in PSB bacterial culture of 82 patients.There were 55 strainsof Gram-negative bacilli(56.1%);20 strains(20.4%) were Gram-positive Cocci;23 strains(23.5%) were fungi. Conclusion The primary pathogenic bacteria were Gram-negative bacilliin lower respiratory tract of the patients with severe pulmonary tuberculosis,and the fungi infection was distinctly rising.It might be related to immunod eficiency,antibiotic abuseand reasonless antituberculosis treatment.

Key words: pulmonary tuberculosis/complication, Respiratory tract infections