Clinical impact of Gram-negative nonfermenters on adults with community-onset bacteremia in the emergency department

Background: To determine clinical predictors and impact of Gram-negative nonfermenters (GNNFs) infections among adults with community-onset bacteremia in the emergency department (ED). Methods: Adults with bacteremia visiting the ED from January 2007 to June 2008 were identified retrospectively. Demographic characteristics, underlying illnesses, clinical conditions, bacteremic pathogens, antimicrobial agents, and outcome, were retrieved from chart records. Results: After the exclusion of 261 patients with contamination of blood cultures and 24 patients referred from other hospitals, 518 adults with community-onset bacteremia were eligible; their mean age was 65.1 years, with slight predominance of female (262 patients, 50.6%). Of a total of 565 bacteremic isolates, Escherichia coli (228 isolates, 40.4%) and Klebsiella pneumoniae (100, 17.7%) were the major microorganisms. GNNFs caused bacteremia in 31 (6.0%) patients. A higher proportion of inappropriate antibiotic therapy in the ED (87.1% vs. 26.5%, p<0.001) and higher 28-day crude mortality rate (19.4% vs. 8.4%, p=0.05) were observed in bacteremic patients caused by GNNFs than those not caused by GNNFs. In further analysis of Kaplan-Meier survival curve, patients with GNNF bacteremia had a worse outcome than those due to other pathogens ( p=0.04). Multivariate analysis revealed that the independent predictors related to GNNF bacteremia included surgery during previous 4 weeks prior to ED arrival [odds ratio (OR), 10.79; 95% confidence interval (CI), 1.84-63.24; p=0.01], residents in long-term healthcare facilities (OR, 4.62; 95% CI, 2.08-10.29; p<0.001), and malignancy (OR, 2.24; 95% CI, 1.10-5.40; p=0.02). Conclusion: For adults with bacteremia visiting the ED, GNNF is associated with a higher mortality rate and more inappropriate empirical antibiotic therapy in the ED. To allow early administration of empirical antibiotics, several clinical predictors of GNNF infections were identified.