Community-acquired pneumonia in chronic obstructive pulmonary disease

Purpose of review The aim of this study was to discuss the literature on community-acquired pneumonia (CAP) in patients with chronic obstructive pulmonary disease (COPD). Recent findings Well designed studies show that COPD is the strongest risk factor for development of CAP. Lung microbiome, abnormal lung immunity and pathogen virulence are important components of the pathogenesis of CAP in COPD. The cause of CAP in patients with COPD is similar to that of non-COPD patients. However, patients with COPD are at an increased risk of infection by Gram-negative bacilli, including Pseudomonas aeruginosa. Empiric treatment regimens for CAP in COPD should contemplate the most common pathogens, and consideration should be given for the coverage of Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus depending on the severity of CAP, severity of COPD or prior isolation of these pathogens. COPD has not been consistently shown to be an independent risk factor for worse short-term outcomes in patients with CAP. In a long-term study, COPD is associated with worse outcomes in these patients. Research focused on lung microbiome and abnormal lug immunity in patients with COPD should be prioritized. Further clinical research should try to consolidate the role of additional treatment approaches such as immunomodulating medications in COPD patients with CAP.