The Impact of a Rapid Diagnostic for Bloodstream Infections Without Antimicrobial Stewardship Intervention

Background: Bloodstream infections (BSIs) remain a significant cause of morbidity and mortality among hospitalized patients, often leading to prolonged lengths of stay and increased healthcare costs. Early, appropriate antimicrobial therapy for BSIs is associated with improved outcomes. Rapid molecular assays have been developed to facilitate earlier identification of organisms causing BSIs. However, their impact on clinical outcomes and antimicrobial use is variable and often contingent upon antimicrobial stewardship (AS) review of results and guidance on antimicrobial prescribing. The FilmArray^©Blood Culture Identification (BCID) panel was implemented at the University of Utah Hospital in November 2014. Given local resource constraints, we aimed to evaluate the impact of the BCID with template reports and results called to ordering providers in the absence of AS support.

Methods: We performed a pre-post quasi-experimental study to analyze the impact of the BCID with customized template reports on time to appropriate antimicrobial therapy. Patients were included if they had at least one positive aerobic blood culture during the study period (3 months pre and post BCID). Patients with positive blood cultures within two weeks of a previously evaluable episode with the same organism were excluded.

Results: 278 patients with BSIs were included: 144 pre-BCID and 134 post-BCID. Use of the BCID led to more rapid organism identification as compared to standard methodologies (1.9 vs. 39.6 hours, P<0.001). The BCID panel was associated with reduced median time to appropriate antimicrobial therapy (1.5 vs. 2 days, P = 0.007). Additionally, BCID was associated with shortened time to appropriate antimicrobial therapy in multivariable Cox proportional hazards modeling adjusting for age, ICU admission, severity of illness and immunosuppression (HR=1.37, 95% CI 1.06-1.76, P=0.02).

Conclusion: Use of the BCID panel led to more rapid organism identification in BSIs and improvement in antimicrobial use. Although AS review of BCID results and guidance on therapy is likely to contribute to further improvements in antimicrobial use, our results suggest use of the BCID with customized template result reports can reduce inappropriate antimicrobial prescribing.