1Rello J,Torres A.Microbial causes of ventilator-associated pneumonia.Semin Respir Infec,1996,11：24～31.
2Lennox A,Lisa P,Dminique M,et al.Antimicrobial resistance in isolates from inpatients and outpatients in the United States：Increasing importance of the Intensive Care Unit.Clin Infect Dis,1997,24：211.
4Hanberger H,Garcia-Rodriguez JA,Gobernado M,et al.Antibiotic susceptibility among aerobic gram-negative bacilli in intensive care unit in 5 European Countries.French and Potuguese ICU Study Groups.JAMA,1999,281（1）：67～71.
5Lee SC,Fung Cp,Liu PY,et al.Nosocomial infections with Ceftazidime-resistant Pseudomonas aeruginosa：risk factors and outcome.Infect Control Hosp Epidemiol,1999,20（3）：205.
6Rahal JJ,Urban C,Horn D,et al.Class restriction of cephalosporin use to control total cephalosporin resistance in nosocomial klebsiella.JAMA,1998,280（14）：1233.
2Vestbo J,Hurd S S,AgustíA G,et al.Global strategy for the diagnosis,management,and prevention of chronic obstructive pulmonary disease:GOLD executive summary[J].Am J Respir Crit Care Med,2013,187(4):347.
3Wang H,Gu X,Weng Y,et al.Quantitative analysis of pathogens in the lower respiratory tract of patients with chronic obstructive pulmonary disease[J].BMC Pulm Med,2015,15(1):94.
4Stockley R A,O'Brien C,Pye A,et al.Relationship of sputum color to nature and outpatient management of acute exacerbations of COPD.2000[J].Chest,2009,136(6):e30.
5Lai C C,Chen S Y,Wang C Y,et al.Diagnostic value of procalcitonin for bacterial infection in elderly patients in the emergency department[J].J Am Geriatr Soc,2010,58(3):518.
6Lee S H,Chan R C,Wu J Y,et al.Diagnostic value of procalcitonin for bacterial infection in elderly patients-a systemic review and meta-analysis[J].Int J Clin Pract,2013,67(12):1350.
7Cuquemelle E,Soulis F,Villers D,et al.Can procalcitonin help identify associated bacterial infection in patients with severe influenza pneumonia?A multicentre study[J].Intensive Care Med,2011,37(5):796.
