Abstract: OBJECTIVE To investigate the drug resistance of multidrug-resistant organism（MDRO）and prognosis in patients with pulmonary infection,so as to provide reference for prevention and treatment of patients with pulmonary infection caused by MDRO.METHODS 200 patients with pulmonary infection treated in the hospital from Jan.2017-Dec.2017 were enrolled in the study,sputum samples were collected for bacterial culture,bacterial strain identification and drug sensitive test,and meanwhile the treatment with sensitive antimicrobial agents was given and the outcome of treatment in patients with pulmonary infection was observed.RESULTS Pathogens were isolated from the sputum samples of 178 patients,with a positive rate of 89.00%,among which 132 cases were non-MDRO infection and 46 cases were MDRO infection.In cases with MDRO infection,42 cases were single infection,and 4 cases were multiple infection.A total of 50 MDRO strains were detected from the 46 MDRO-infected patients,among which there were 41 strains of gram-negative bacteria,accounting for 82.00%,dominated by Acinetobacter baumannii and Klebsiella pneumoniae,and 9 strains of gram-positive bacteria,accounting for18.00%,dominated by Pseudomonas aeruginosa.Staphylococcus aureus MDRO strains were completely resistance to penicillin,cefazolin sodium,benzazole penicillin,piperacillin/triazolamide and erythromycin,and the resistance rates to imipenem,ciprofloxacin,levofloxacin,gentamicin and tetracycline were all＞70%,but they were susceptible to vancomycin.Most of gram-negative MDRO bacteria were completely resistant to the first generation of cephalosporins and penicillins,while their resistance rate to imipenem was relatively low.The deterioration rate of patients with MDRO infection was 15.22%（7/46）,significantly higher than that of patients with non-MDRO infection（P=0.013）.CONCLUSION MDRO infection rate is high in patients with pulmonary infection,with gram-negative bacteria as the main pathogens,which have wide-spectrum resistance to antimicrobial agents.MDRO infection can increase the incidence of adverse outcomes in patients.