Factors contributing to mortality in healthcare-associated pneumonia HCAP have not been investigated fully. We reviewed the etiology and identi ed prognostic factors of HCAP in hospitalized patients. We conducted a retrospective study of 500 Japanese patients with HCAP to assess these factors, with special emphasis on microbial etiology. Patients with HCAP were older 73.4 11.4 years , more predominantly male 74.4 , and had more smoking history and comorbidity than did community-acquired

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... a CAP patients. Microbes were identi ed in 52.8 of HCAP patients. The most frequent causative microbial agents were Streptococcus pneumoniae n 108, 21.6 , influenza virus n 47, 9.4 , and Pseudomonas aeruginosa n 40, 8.0 . Multiple drug-resistant MDR pathogens were more frequent in HCAP patients 9.8 than CAP patients. Overall, 47 HCAP patients 9.4 died, with mortality being higher in HCAP than CAP patients. The three leading causes of non-survival from HCAP were S. pneumoniae, in uenza virus, and P. aeruginosa. MDR pathogens accounted for 21.3 of non-survivors. Multivariate analysis revealed disease severity on admission and treatment failure of initial antibiotics as independent factors for 30-day mortality. Among patients with treatment failure of initial antibiotics, 29.9 had received appropriate antibiotics. The most frequent pathogens in HCAP were S. pneumoniae, in uenza virus, and P. aeruginosa, in both survivors and nonsurvivors. Disease severity on admission and treatment failure of initial antibiotics were independent factors for mortality. MDR pathogens are important therapeutic targets to mitigate negative results, and treatment strategies other than antibiotic selection are also required.