Impact of inappropriate empirical antibiotic therapy on outcome of bacteremic adults visiting the ED

Abstract Objectives To investigate the clinical impact of inappropriate empirical antibiotics on patient outcome and determine the risk factors for mortality in bacteremic adults who visited the emergency department (ED). Methods Bacteremic adults visiting the ED from January 2007 to June 2008 were identified retrospectively. Demographic characteristics, clinical conditions, bacteremic pathogens, antimicrobial agents, and outcomes were determined from chart records. Results The total of 454 eligible bacteremic adults were included in the analysis; excluded from the study were another 261 patients with contaminated blood cultures and 64 patients with ED stays of less than 24 hours. Among the included individuals, the mean age was 64.6 years, with a small predominance of males (230 patients, 50.7%). Of a total 494 bacteremic isolates, Escherichia coli (206, 41.7%) and Klebsiella species (81, 16.4%) were the most frequently encountered microorganisms. A lower 28-day mortality rate was demonstrated in bacteremic patients treated with appropriate antibiotics than that in those with inappropriate antibiotics or that in those with no antibiotic therapy, as judged by Kaplan-Meier survival curves ( P = .01). Moreover, the differences among these three groups achieved higher significance ( P = .002) in critically ill patients (Pittsburgh bacteremia scores of ≥4 points). In multivariate analyses, inappropriate antibiotic therapy in the ED was associated independently with mortality at 28 days (odds ratio, 2.26; 95% confidence interval, 1.01-5.13; P = .04). Conclusions For bacteremic adults visiting the ED, their outcomes were favorable following appropriate antibiotics, compared to treatment with inappropriate antibiotics or no antibiotics.