Assessing the Impact of an Automatic Antimicrobial Stewardship Review of Positive Blood Cultures in Patients with Gram-Negative or Gram-Positive Bloodstream Infections

Abstract

Background. Bloodstream infections (BSI) are associated with high morbidity and mortality. Studies evaluating rapid diagnostic tests in conjunction with antimicrobial stewardship (AS) measures for BSI have demonstrated improved outcomes. We endeavored to study whether standard identification of BSI coupled with AS could improve time to optimal antibiotics. Methods. We performed a retrospective, quasi-experimental study of adult patients with bacterial BSI between 1 December 2014 to 28 February 2015 (preintervention) and 1 December 2015 to 20 February 2016 (intervention). During the intervention, the AS team received a once-daily list of patients with new BSI from the microbiology laboratory, reviewed available data in the chart at the time of positive blood culture, and made recommendations to the primary service if deemed appropriate. Before the intervention, the AS team was available for consultation upon request by the primary service. Baseline continuous variables were analyzed using student t-test or Wilcoxon sum rank test, while categorical variables were compared using a χ2 test. Inhospital survival was evaluated by the Kaplan-Meier method with log rank statistics. Results. Of the 264 patients included in the study, 134 were in the preintervention group and 130 in the intervention group. The mean age was 60 years, and 55% of patients were male. There were more patients with chronic kidney disease and on dialysis in the preintervention group. The most common organisms included Escherichia coli (26%) and Staphylococcus aureus (23%). Time to optimal therapy was shorter in the intervention group than the preintervention group (56 ± 50 hours versus 86 ± 95 hours, p =0.05). The percentage of de-escalation events were similar between both groups (81% versus 73%, p =0.24). No differences in duration of intensive care unit or hospital stay from positive BSI, rate of Clostridium difficile infection, or in-hospital mortality were noted. Conclusion. Daily review of positive BSI can be considered as an antimicrobial stewardship strategy to shorten time to optimal antimicrobial therapy. Real-time notifications for positive BSI or more frequent reviews of positive BSI may have an even larger impact on antimicrobial prescribing and patient outcomes.