Risk factor-based analysis of community-acquired pneumonia, healthcare-associated pneumonia and hospital-acquired pneumonia: Microbiological distribution, antibiotic resistance, and clinical outcomes.

HCAP showed higher rates of P. aeruginosa and MRSA infections than CAP. Empirical antipseudomonal therapy should be considered in the treatment of HCAP. Prior isolation of P. aeruginosa was the most important risk factor for P. aeruginosa infection.