Background:Healthcare-associated pneumonia (HCAP) is associated with drug-resistant pathogens and high mortality,and there is no clear evidence that this is due to inappropriate antibiotic therapy.This study was to elucidate the clinical features,pathogens,therapy,and outcomes of HCAP,and to clarify the risk factors for drug-resistant pathogens and prognosis.Methods:Retrospective observational study among hospitalized patients with HCAP over 10 years.The primary outcome was 30-day all-cause hospital mortality after admission.Demographics (age,gender,clinical features,and comorbidities),dates of admission,discharge and/or death,hospitalization costs,microbiological results,chest imaging studies,and CURB-65 were analyzed.Antibiotics,admission to Intensive Care Unit (ICU),mechanical ventilation,and pneumonia prognosis were recorded.Patients were dichotomized based on CURB-65 (low-vs.high-risk).Results:Among 612 patients (mean age of 70.7 years),88.4％ had at least one comorbidity.Commonly detected pathogens were Acinetobacter baumannii,Pseudomonas aeruginosa,and coagulase-negative staphylococci.Initial monotherapy with β-lactam antibiotics was the most common initial therapy (50％).Mean age,length of stay,hospitalization expenses,ICU admission,mechanical ventilation use,malignancies,and detection rate for P.aeruginosa,and Staphylococcus aureus were higher in the high-risk group compared with the low-risk group.CURB-65 ≥3,malignancies,and mechanical ventilation were associated with an increased mortality.Logistic regression analysis showed that cerebrovascular diseases and being bedridden were independent risk factors for HCAR.Conclusion:Initial treatment of HCAP with broad-spectrum antibiotics could be an appropriate approach.CURB-65 ≥3,malignancies,and mechanical ventilation may result in an increased mortality.