Background: Introducing rapid diagnostic assays combined with antimicrobial stewardship team (AST) interventions have led to improvements in time to effective antimicrobial therapy in patients with bloodstream infections (BSI). Prescribing outcomes in the context of a rapid diagnostic assay alone have not been determined.
Methods: The standard empiric broad-spectrum antimicrobial regimen for sepsis at our institution is vancomycin and piperacillin/tazobactam. In mid-2014, a PCR-based rapid diagnostic assay, FilmArray blood culture identification (BCID) panel, was implemented in 2014 without concomitant AST intervention. The assay detects specific bacterial species as well as genes associated with antimicrobial resistance (e.g. vanA and Klebsiella pneumoniae carbapenemases). A retrospective chart review of inpatient BSI in 2014 requiring escalation from the standard regimen (i.e., vancomycin resistant Enterococcus, carbapenem resistant Enterobacteriaceae, or Acinetobacter baumannii) was conducted to analyze the impact of the assay. Primary outcomes included time to effective antibiotics, length of stay, and 14 day mortality.
Results: 83 BSIs were included in the final analysis: 32 in the pre-BCID group and 51 in the post-BCID group. BCID decreased median time to effective therapy from the time blood cultures were ordered (31.9 hours vs. 22.3 hours, p = 0.008) and from notification time of Gram's stain results (13.8 hours vs. 3.7 hours, p = 0.009). Length of stay after bacteremia onset was significantly longer in the pre-BCID group (19 days vs. 14 days, p = 0.021). ICU length of stay was not significantly different between the groups (7.5 vs. 5 days, p = 0.059). There was no significant difference in 14 day mortality between the groups (21.9% vs 31.4%, p = 0.347). In a multivariable model controlling for ICU status, delay in source control, and Pitt bacteremia score, there was no significant difference in 14 day mortality between the groups (p = 0.591).
Conclusion: BCID significantly reduced time to effective antibiotic therapy in patients with multidrug-resistant BSI without the concomitant use of AST intervention. Further investigation is needed to determine how to best deploy AST interventions strategically.
C. J. Kubin, None
S. Whittier, None
E. Y. Furuya, None