O411 Community-acquired pneumonia caused by Pseudomonas aeruginosa: incidence, risk factors, and outcome

Abstract

Although numerous articles have demonstrated that recommended empiric antimicrobial regimens are associated with decreased mortality at 30 days, there is controversy over whether appropriate antibiotic selection has a beneficial impact on mortality within the first 48 to 96 hours after admission. Our aim was to determine whether the use of guideline-concordant antibiotic therapy is associated with decreased mortality within the first 48 hours after admission for patients with pneumonia.A retrospective cohort study was conducted at two tertiary teaching hospitals in San Antonio, Texas. A propensity score was used to balance the covariates associated with the use of guideline-concordant antimicrobial therapy. A multivariable logistic regression model was used to assess the association between mortality within 48 hours and the use of guideline-concordant antibiotic therapy, after adjusting for potential confounders including the propensity score.Information was obtained on 787 patients with community-acquired pneumonia. The median age was 60 years, 79% were male, and 20% were initially admitted to the intensive care unit. At presentation 52% of subjects were low risk, 34% were moderate risk, and 14% were high risk. Within the first 48 hours, 20 patients died. After adjustment for potential confounders, the use of guideline-concordant antimicrobial therapy (odds ratio 0.37, 95% confidence interval, 0.14-0.95) was significantly associated with decreased mortality at 48 hours after admission.Using initial empiric guideline-concordant antimicrobial therapy is associated with decreased mortality at 48 hours. Further research needs to investigate methods to ensure that patients with community-acquired pneumonia are treated with appropriate antimicrobial therapies.