Methods: This study was a retrospective chart review. All adult patients with a blood culture positive for MRSA from July 2012 to June 2013 (Prompt) and July 2013 to June 2014 (Turbidity) were considered for inclusion. Patients were excluded if they had a documented vancomycin or daptomycin allergy, polymicrobial bacteremia, concomitant pneumonia, received vancomycin or daptomycin for < 72 hours, or were transferred from another facility. The primary endpoint was the difference in daptomycin utilization between the Prompt and Turbidity arms. Secondary endpoints included differences between arms in clinical failure, defined as a composite of persistent bacteremia and 30-day in-hospital mortality, percent of patients with an initial vancomycin MIC of 2 mcg/mL, length of stay, hospital readmission, and recurrence of MRSA bacteremia.
Results: A total of 54 patients met criteria for study inclusion (Prompt = 31, Turbidity = 23). The Turbidity arm had a significant reduction in daptomycin utilization compared to the Prompt arm (11.9 and 30.4 days of daptomycin therapy per 100 days of anti-MRSA therapy, respectively; p = < 0.001) while clinical failure occurred at a similar rate in both the Turbidity and Prompt arms (26.1% and 25.8%, respectively; p = 0.981). There was also a significantly lower percent of patients with an initial vancomycin MIC of 2 mcg/mL in the Turbidity vs. Prompt arm (13% and 38.7%, respectively; p = 0.022).
Conclusion: For MRSA bacteremia, lower reported MIC values observed using the Turbidity method may lead to decreased daptomycin utilization without impacting clinical outcomes. Larger studies are needed to further validate these results.
E. King, None
J. Mcguire, None
J. Maslow, None