Abstract: Objective To investigate the characteristics of the distribution and drug resistant of pathogenicbacteria in lower respiratory tract of pulmonary tuberculosis cases ,and analyze the clinical manifestation w hen co m plicated with pneu monia . Methods 156 cases with pulmonary tuberculosis were taken for strain identification and sensi tivity test to antibiotic in vitro afterthe result positive of bacteria and fungus culture . Results All of 239 cases for pathogenicbacterialstrains were found in sputums bacterial culture of 156 patients. There were 210 strains of gram negative bacilli(87.9 % ) ；fungus were 21(8.8 % ) ；gram positive cocci were 8(3.3 % ) . The detection of drug sensitive test suggested thatciprofloxacin had the highest susceptibility ,rates was 60.6 % ,and rifampicin had thelowestsusceptibility ,only 4.1 % . Conclu sion The primary pathogenic bacteria were gram negative bacilliin lower respiratory tract of pulmonary tuberculosis patients . This may be related toim munodeficiency ,abuse antibiotic and treated with antituberculosis drugs .

Key words: Tuberculosis, pulm onary, Respiratory tract, Pathogenic bacteria