Bacteriological differences between COPD exacerbation and community-acquired pneumonia.

OBJECTIVE To study the differences in pathogen distribution and antibiotic susceptibility between patients with COPD exacerbation and patients with community-acquired pneumonia, and develop guidance for antibiotic treatment of those conditions. METHODS We retrospectively analyzed the medical records of 586 COPD-exacerbation patients and 345 community-acquired-pneumonia patients from January 2007 to December 2008, including sputum culture results, antibiotic susceptibilities of the microorganisms, and clinical characteristics. RESULTS 276 (47%) of the COPD-exacerbation patients, and 183 (53%) of the community-acquired-pneumonia patients had a positive sputum culture. In order, the most common pathogens in the COPD-exacerbation patients were Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Acinetobacter baumannii, and Haemophilus influenzae. The most common pathogens in the community-acquired-pneumonia patients were Streptococcus pneumoniae, H. influenzae, K. pneumoniae, S. aureus, and E. coli. CONCLUSIONS P. aeruginosa was the most common pathogen in our patients with COPD exacerbation, and S. pneumoniae was the most common in our patients with community-acquired pneumonia. P. aeruginosa is especially common in the patients with serious or extremely serious COPD.