Background: Source control, targeted antibiotic therapy, and appropriate duration of therapy are the tenets of management of S. aureus
bacteremia (SAB). This study aimed to increase appropriateness of treatment for SAB at our academic medical center.
Methods: A quasi-experimental design was used to analyze periods before and after implementation of a SAB treatment protocol. During the intervention period, an ID pharmacist left a structured medical note in the electronic medical record at day 2 and day 5 after positive S. aureus blood cultures. Appropriate therapy was defined as appropriate antistaphylococcal therapy and duration of therapy documented as 2 weeks for uncomplicated bacteremia or 4-6 weeks for complicated bacteremia. Appropriate antistaphylococcal therapy consisted of nafcillin or cefazolin for methicillin-susceptible S. aureus (MSSA) and vancomycin, daptomycin, and/or ceftaroline for methicillin-resistant S. aureus (MRSA).
Results: One hundred eighty-two patients were analyzed: 106 in the pre-implementation group and 76 in the post-implementation group. The median age was 50 years (IQR 35.5-63), 58% of the cohort was male, 26% of the cohort had a history of IV drug abuse. Common sources of infection were vascular access (23%), osteoarticular (20%), and respiratory tract (19%). The rate of MRSA was 59%. Complicated bacteremia comprised 63% of cases. Seventy-two percent of patients in the pre group and 86% of patients in the post group were on appropriate therapy (P=0.03). In patients with MSSA, 73% of patients in the pre group and 81% of patients in the post group were treated with nafcillin or cefazolin. In patients with MRSA, 24% in the pre group and 49% in the post group were definitively treated with vancomycin. Median duration of therapy was 27 days in the pre group and 19 days in the post group. Mortality was significantly lower in patients who received appropriate therapy compared to patients who received inappropriate therapy (16% vs. 37%, P=0.008).
Conclusion: A pharmacist-driven, systematic approach to management of SAB significantly increases the number of patients on appropriate therapy. Patients who receive appropriate therapy have significantly reduced mortality compared to patients who receive inappropriate therapy.